It depends how you use car assistance devices. It you drink Musk's cooldaid about the autopilot it's bullshit. People who use these technologies to do something else/let them get distracted are idiots and tbh, should be punished severely.

But there is ample scientific data that e.g. radar based speed control/adaptive cruise control does reduce injury rates as it let people stay focused for longer as less concentration is used.

Basically you have a (individual )envelope of concentration/focus that you can stay reasonably focused. The time limit how long you can do so is influenced by ones general mental condition, experience, individual constitution on that day, driving circumstances, time, etc. On average it is around 2.5h.

With well designed assistance systems this period can be prolonged by up to 1h, 45min on average and cases where we have a bad day profit more. And as we are all idiots who think we can drive 4h/5h/6h/+X straight the time we are not concentrated enough is reduced significantly.

And of course there are pure security oriented systems that simply do things better than humans - automatic obstacle recognition and breaking systems are a good example. There is literally a kid not being injured or dead because my car has one (as it is the European law by now) - crossed a inner city street without looking, between two large vans parked on the side... No chance to see the kid. And even with 30km/h a full front collision can kill. The car was brought to a full stop before I even recognised what happend.

Source: one of my best friends is a researcher on that topic for a major university.