Sorry, I realize I said looking at the trailer hitch, but I primarily meant using the camera to check the load on a trailer. I totally agree that there shouldn't be anything happening with the hitch, and if there is, there's a bigger problem than what a camera is probably going to help with.

However, when hauling a load on a flatbed trailer, there is always the possibility that something could shift in the load, and maybe as a result a strap could be loose and flopping a bit. It's just a nice feature to be able to glance at the rear camera and confirm that everything is still good back there. I know it's not a necessity, but it is a nice option.
And I agree on the mirrors. I don't really like using a backup camera as my main view when backing up. I'm still in the habit of using my mirrors as well. Where the camera comes in really handy is, as I mentioned, on the rear of a cargo trailer. There's no way to see what's directly behind your enclosed trailer (or camper, if that's what is being pulled) with mirrors, and it's really nice to look at the screen and know some kid or other small car