I'm going to keep picking until you guys get annoyed with me (or realise i'm right rawww)
Well
google calendar and email work offline on your PC (bold because a lot of people don't realise this), so you don't need access to the web all the time. Calendar & contacts synced via the cloud, updated wherever you are. Apps (programs), well its done all through your phone. Maps done via turn by turn nav/google maps.
You talk about previously being able to manage your phone via your PC, how about managing your information from whichever device you are currently using? The device doesn't matter to me anymore, I know I can get the latest up to date copy of my information anywhere, with nothing holding me back. New way of thinking but for me, infinitely better than the old way.
I used to use Thunderbird, and I did love it. However, in line with the new way of doing things, having a dedicated email client is akin to having locks around my feet, slowing me down, stopping me from accessing my information when and where I want it.
Why should I be tied down to using a program installed on one of my PCs to manage all my information? I don't need that holding me back. Instead I prefer to be able to access all my information, contacts, calendar and emails from whichever device is at that moment in time closest and easiest for me to get to. In full knowledge that without any intervention from me, it will be the latest copy (well its not a copy, it is itself) of that information!