Rooting isn't as special as it may seem, but its purpose is to offer you more control over your device. It's basically unlocking permission control over your device that manufacturers deemed you shouldn't have. (For good reason, of course.)
I actually won't buy a device unless root has been achieved. I jumped the gun for the Spirit because I was impressed with the phone. For most devices, carriers and manufacturers load a bunch of unnecessary crapware. Being able to remove that crapware is important to me. If that's one of your concerns, then you should probably root. Furthermore, in your other thread, you were wanting to have a stock Android experience. When ROMs are available, you will need root in order to install said ROMs.
There's a how-to over in the "all things root" section that is very simple to follow. The process for rooting the Spirit is a lot easier than some devices. It's literally "one-click" and you're done. The process is entirely reversible, and shouldn't have any strange side effects.