Installing the rear camera was much easier than I thought it would be...doing my ex's 4Runner with the sliding window was 20x worse. I wouldn't want to do that again.
For the TJ, I ran power from the driver-side reverse light up into the tub, then along the wheel well, then behind the plastic cover on the left of the driver seat and up through the dash to the stereo. It's legit easy.
The camera helped calm my nerves when backing up around people with my 35 inch tire that used to be up higher. There were students constanctly walking behind my Jeep wearing head phones when I'd try back out. And little people in parking lots. I don't worry about it much now that I have the option to verify.
The main benefit at this point, is just having the map and music screen bigger so I can glance quicker and put my eyes back on the road. None of that is necessary, but it is nice.