That's a Honda trick. Toyota doesn't know that trick. A friend has that on their new CR-V. It's pretty handy.
No curvy backup lines for the US. Other countries' Primes do get the curves, from what I've see in other posts, including of course the Japanese editions as in the Prime video in the O.P.
I've never had a backup camera before except on cars I was borrowing or renting. Now that I do, I'm actually glad they don't respond to the steering wheel. It's nice to have a fixed reference for alignment with fixed targets like parking lines and walls.
Our BMW i3-REx curves the lines that the Prius Prime Plus holds as fixed. We're using the same work and business sites with both cars. The curved lines makes it slightly easier to fine tuned the steering when backing into a spot but both can be misleading. It is very important to use your outside view and rear mirrors and actually turn your head to make sure everything is clear. This is more important than curved or fixed, backup lines. The lines help, especially when parallel parking to adjust final distance to curb or car, but fixed or curved, they are not alone a magic bullet. Bob Wilson
Completely agree. I still find it far easier to back into a parking space, even if I'm doing it from an angle, by using the outside mirrors. In the last few feet the camera makes it easier to fine tune parallelism (which is why I like the fixed lines) and the stopping location.