True. But with a paper printout, the need for notetaking is also resolved. A student cannot focus on an LED screen for an entire lecture, and take notes at the same time without missing something on the LED screen, just as a student cannot focus 100% of their attention on a terp and take notes without missing part of a signed lecture, nor focus 100% of their attention on lip reading and take notes at the same time without missing part of what is being said.
I use CART full time at school, so this is something I'm very familiar with. And I've used it both with residual (and now implanted) hearing, and with no auditory input whatsoever. There's a few things you seem to be missing that may be specific to the way your school does CART, but are not universal (and in my experience using CART in a variety of geographic reasons, are uncommon).
First, LED screens are not common in an environment where there's only one or two clients. They're often used in theater, or for conferences, but don't show up in the classroom all that much. Laptop screens are much more common, and much easier to read. (Not least because text stays up on the screen long enough that it's possible to look at the board or the professor, then back at the screen.)
And while I would agree that taking notes can be difficult while using CART, CART does generate a transcript that can be saved and sent to the student. I've always received transcripts at most a day or two after class (my reporters generally clean up the transcript a bit). That is something that's governed by the school's contract with the reporter or their agency; it's not a technical limitation of CART.