Some ISPs (verizon?) do similar things, where if you use their app then you're allowed to stream as much as you want. But I'm not sure whether that runs afoul of neutrality laws.
This is admittedly a weak argument, since companies would end up eating the cost, further entrenching the existing monopolies. But they were looking for arguments in favor of NN.
There are other contexts where non-neutrality might be useful: A local startup once tried to roll out a lower-latency service for gaming, based on intelligent routing. It was unlikely to succeed, but even if it were technically possible it would definitely violate NN to be prioritizing/rerouting certain classes of traffic.
This is not true at all.
Net neutrality rules allow for "Reasonable Network Management" which includes prioritizing classes of traffic. Here's a discussion on it https://www.reddit.com/r/networking/comments/6nddmx/does_net...
You could add more priorities in between, etc. as needed.