Ironically - bad ones will effectively try to kill you less.
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.
Everyone that I have heard from who uses one say that it reduces the monotonous mental load and frees up their brain to focus more on being aware of other drivers and what's happening on the road, rather than worrying about their speed and exact steering.
People report being more alert and more aware of things about to go wrong.