Probably would have been better if Tesla branded it "co-pilot". Autopilot while technically correct doesn't function the way people assume it does.

Can't Tesla just refund them the cost of the car and be done with it? Why would these plaintiffs receive anything beyond that?

Not making a judgement on whether their claims are accurate, but they are arguing Tesla intentionally made false and misleading advertisements.

Companies should not be allowed to false advertise with impunity. A mere refund is not sufficient to stop the behavior.