(sorry, I didn't notice this reply back there)
1) It's also easy to just drive your car, never changing the oil, checking the brakes, etc. That doesn't mean it's the proper way to handle the tool (your car).
Easy is not necessarily correct.
2) It's also easy to prop doors open when you're moving into/out of a building. They heavily discourage this at dorms in urban college campuses. Sure, it's easy. And every year, someone does it. And every year, some local criminal uses it as an easy way to sneak into the building. If everyone's lucky, it only results in some theft. It occasionally results in a rape.
Easy is often "not safe". (easy is, in fact, often the opposite of safe/secure).
Both of those lessons apply to email attachments. Email is not a "file transfer protocol", nor a "file sharing protocol". It also offers little to no protection of the message in-transit (there are ways around that, but none of them are perfect, and none of them offer long term protection), meaning it's also not a safe mechanism for file sharing/protection. It also offers no optimizations nor integrations with file management mechanisms, making it a resource pig when it comes to trying to shoe-horn "file storage/sharing/transfer" into email protocols.
Really. People who think that email is "a great way to share files" are on the same intellectual level as people who drive their cars, without maintenance, until the engine literally falls apart ... and/or people whose selfish short-sighted pursuit of their own convenience gets other people robbed.
(no, I don't consider that last bit to be sensationalist nor an exaggeration, considering the number of people I've seen wanting to send passwords, financial information, or health information, through email systems).
You can always count on a specialist to arrogantly presume his intellectual superiority and the primacy of his experience and of his own POV. They tend to issue petty, sophistic statements oozing in childhood resentment, lacking in proportionality, tact, and usually truth. These rash statements are meant to convey to us that that it is in fact THEY that are right, that they are the genius tormented by the hordes of morons. But hey, some buy hummers, some become sysadmins...
ANYWAY, I've got some time to kill, so here's some food for thought, if your trekkie/RPG mind can handle it. I wonder if you've seen the light on your own in the 4 years since your post:
* Consider the average computer user, ACE (secretary, mom, physicist, doctor -- anyone who's not a sysadmin or anyone else who actually likes to spend time dicking around in config files and daemon settings like some glorified plumber or accountant). If ACE (not you) wants to send someone a PDF, a Word file, a couple pictures, what do you think is more convenient and faster for ACE? Attaching the document to an email, or setting up a dropbox account + coordinating, or using Google docs (which presumes that ACE is a gmail user)? And don't forget another reason attachments are useful: searchable context. File-sharing services don't offer any of that, or if there is something like it, nobody is using it.
* Apparently, ease of use isn't a priority for you. That puts the cart before the horse. Broadly speaking, software should cater to people, not the other way around. The argument from correctness is a fallacy, and it's an arrogant fallacy at that, one that is dying with the advent of agile where customer use is heavily accented (sometimes to a fault). It's the same presumption that made user interfaces designed by most software engineers unusable and unintuitive. Your job (along the the engineer's) is to make the software work optimally for its current users and their habits. It is not the user's job to operate in a way that makes your job easier. *You* are providing a service. If the service is suffering because of the way users use it, then it's generally a flaw in the service.
* Your examples are riddles with category errors, poor comparisons, shallow analogies. Propping a dorm room open with a book is not even remotely similar to sending attachments. The only thing in common they have is that they make something easy. Leaving yourself logged into your email account on a publicly accessibly computer is analogous (although not proportional). Rape generally occurs between people who know each other (if that is the strength of your argument, then consider that houses not surrounded by a moat makes them more vulnerable to terrorists placing bombs in the basement). Ease is opposite of safe/secure? Again, shallow comparison rooted in equivocation. What kind of ease? Ease of say breaking encryption or easy of logging in without too much hoopla and whizzbang?
* The car example isn't even worth discussing.
* Preemptive strike, because my experience tells me sysadmins are either people with (barely) functioning autism or petty smartasses: I am not claiming that ANY user activity should be accommodated in the formal meaning of the word. Let's stick to how people generally use computers. And besides, computer software can be written to constrain behavior, so easing users into a new way of using the software (perhaps by providing new easy, sensible ways to realize their goals) is fully within the means of software engineering. It's not like users who use attachments are the only thing standing in between you and some utopia.
* Consider that email is a basic staple of what the internet is about (hell, it existed before the WWW did). All the other recent innovations are just that: recent. Most people haven't heard of them. Instead of laying the smackdown, why don't you work in some way to shift people in that direction, if you aren't already? Deal with people as they are. I'm sure dealing with you is no walk in the park.
* Commenting on the intellectual level of computer users in the way you do is shallow, petty, rude, and arrogant. My experience, and that of many people, is that people who present themselves this way are generally of a very unintelligent variety. There's also nothing more entertaining than seeing a sysadmin put in a room with a software engineer.
Summary: Why the snarky lecturing attitude? It might command a kind of silly admiration from lonely teenage boys, but for the most part it merely results in you getting ignored. Instead of being rude, be helpful. If you can remedy the situation by observing the technical limitations of a system in relation to its usage and working with software companies to solve it, do it. If you encourage a reasonable change in usage among users, why not. If it's just a crap situation that you have no power over, deal with it.
Now, onto the main point of this thread: I can also confirm that File Station (which I prefer over Astro for a few reasons) can also be used to send attachments that aren't jpegs.