I'm afraid to ask about the bad ones.
That’s the thing about any automations that are just aides. Humans are extremely bad at monitoring machines, and if aide system is good enough that trick you into thinking it’s actually stand alone and in control, you get complacent very fast, stop pay attention as you convince yourself that automation got it.
So bad level 2 driver assists are so bad, that no one will get complacent, as they give you only very minor help. Really good ones (like comma) can trick you into thinking that they can do much more than they’re designed to do.
People report being more alert and more aware of things about to go wrong.
On a kinda unrelated note: I lately see more and more people watching streams or Tik Tok while driving. If of course you use your newly acquired freedom for that it will lead to more accidents.
This cuts an entire second off of brake times in motorcycling, where it's just a quick hand move that you MUST do (well, 80% of it, the throttle release part) anyway because if you leave the throttle on you will wipe out, so I'd assume it cuts even more for a move like a large lateral move of a leg in a car.
Only issue is that you need to be careful with that foot to avoid keeping your brake lights on at all times.
Note that this might only apply to driving stick. I'm not sure if left foot on brakes is best practice in automatics.