Are you new to TTs & towing or be alone or with a copilot? I would say a shorter TT (like around 20') can get by without a camera but longer around 30' and up a camera may help some folks. $649 seems pretty pricey. RV backup cameras can't all be alike. Have you looked at any reviews? Our wireless Garmin camera image is rather grainy and weak for ex.
I do 100% of the towing (DW has had vertigo issues for a long time). Being as she's never used the truck, she thought everyone would struggle backing up and nothing would do but I had to install a camera for our Garmin GPS. No easy task running the wiring concealed front to back either. I don't like it and don't need it. One thing it can't do is tell you what the distance is from back of TT to objects or end of road surfaces and you need to get out and look to be certain. The camera in our Subaru has a couple of lines on the display to tell you when to stop. Not sure if various backup cameras for RVs are different in this. What would be nice to me is not having the camera image on the GPS and on a separate screen so you can see what's behind you while travelling.
Most of the time DW is with me and when backing into a site, she uses hand signals to guide me in. Works extremely well and waay better than a camera. Took a long time to train her to get the signals correct and consistent tho., lol...