Comment by londons_explore

True, but you can also use a tiny bit of battery power to do "reverse acceleration" to do the final stopping.

It is true that electric braking would continuously use a small amount of power to stay stopped on a slope. That wouldn't be an issue for a few hours, but you couldn't park on a hill for months without ending up with a flat battery, and then eventually the car rolling away.

Small locking pins are the answer to this, rather like the "park" on automatic gearboxes. They are very cheap, since they don't need to do any actual stopping, but merely keeping something stopped.