I kind of feel like that too. If I am ever backing one, someone will be there to guide anyways. The only time I could see it useful is if you are backing up a little bit at the gas station or something and want to make sure no one is behind you.
Trust me, they will move. If they are hanging out 3 ft behind a trailer at a pump they deserve whatever comes their way.
I like the cargo camera and backup camera a lot, especially being able to check on things while driving. I also love the top down camera view which requires you get em all except the trailer cam. I've backed into some VERY tight spaces with a trailer. For me, I know where to put the trailer the issue is how far out can I turn the truck without scraping this tree?
On the topic of backing a TT, skip the technology. When you get to camp, pull to the side of the road your site is on. Then pull past the site and put the truck on the opposite side of the road so the trailer is angled a bit towards your site. Get out, look at things. and drop a couple sticks on the path you need the trailer axles to take, to the inside of where you are turning. If you are real fancy you can use those bright orange jack pads you will be buying for the trailer. Now just back her up, and turn the wheel more less so you are hitting your marks. If you have a really bad site with obstacles on the outside of your turn, have your spotter over there just for that purpose and to make sure your slideouts clear it. People on the internet like to make a big deal out of how hard it is to back a TT, how much they argued with their spouse during it, yadda yadda yadda. It's not. It gets easier the longer you go. Your average bass boat is more difficult. If it was half as hard as some of these people make it out to be, they shouldn't own a TT. Practice this technique for 30 minutes in an empty parking lot with cones and you will be a champ.