It's like a car. Some use it to go from Point A to Point B and keep it stock. Others will put in seat covers, a new sound system and change the wheels. Others will slap in a Glasspack muffler and make changes to the engine.
With rooting you can, like you said, freeze or remove bloatware. You can change the clock speed. There are many apps (like Titanium Backup and battery calibration) that will only work with a rooted phone. You can also install ROMs to really customize your phone.
That being said, I've never rooted my Bionic, nor do I plan to. I bought Motorola because it had the Bionic, not the Bionic because it was made by Motorola. But what happened here has nothing to do with rooting. What they did was install an unofficial update instead of waiting for the OTA update. I've done that myself on both my OG Droid (the change from Eclair to Froyo) and Bionic with no problems. Again, no rooting is required; you simply put the file in the SD card and boot into recovery. The phone will install that file as if it got it OTA. The problem in this case is trying to go back. You can't go back by just uninstalling the update. This time there's no going back.
The Bionic should be getting the 5.9.904 update OTA in a few days. You can install it now by grabbing the file and installing it manually, like I mentioned before. Or you can wait. I plan to wait for this one.
