This. But I think it's better to use marine autopilot system as a comparison - aircraft autopilots are closely monitored by three people (two in the cockpit, one on the ground as air traffic control) and they are combined with all sorts of other automated systems such as ground proximity alerts/etc. Not really comparable to a car.
Autopilot in a boat traditionally just turns the steering wheel for you. And all it does is maintain a desired direction of travel. Not even a destination, just a direction. So when (not if) wind or currents steer you off course, you will have to take over the steering wheel. It also doesn't control speed. All it does, really, is allow you to keep travelling in approximately the right direction.
There are more advanced systems, but that's traditionally how autopilot works. It's very primitive and has been in use for over a hundred years.
Having said that, Tesla hasn't just used the word "autopilot". They also repeatedly refer to their system as "Full Self Driving". And it kinda does that, as long as there isn't a fire truck in the way.