To be accurate it's a "motor" not an engine, and I'm not sure what you mean by the same "area" that holds the car, the rotor will most likely end up in a different position each time you are stopped, and there is nothing to wear out in any case. As I mentioned earlier it will be inefficient and could draw substantial current so using the brakes for hill hold would make more sense.
Try holding the car with the go pedal on a hill at a traffic light; it uses very little power, so it's not
that inefficient. Unfortunately, the car doesn't make it easy to do this well. The accelerator pedal is rather sensitive, and there's a bit of a glitch when the car goes from rolling backwards in "D" to rolling forwards in "D".
In a manual, after backing out of a parking spot, you can shift into first, and let the clutch out slowly to smoothly transition from traveling backwards to traveling forward. You can almost do this in Model S, too, but there's this little hiccup at 0 mph. It's not a big deal, and if Tesla never "fix"es the "problem", I won't think anything less of the company, but I do notice it.
Anyway, yes, I suspect that Tesla will use the parking brake for a hill hold. I just hope the brake releases quickly. It takes a large fraction of a second for it to engage after pressing the "P", so I hope it disengages faster than it engages.
Back on topic, I've tried creep and no creep, and I've driven manuals and automatics. I have a slight preference for no_creep, but I think they both have some advantages. In general, I think it's easier to smoothly come to a stop at a stop light without creep. With creep, it's really an art to let off the correct amount of pressure from the brake at the right time to avoid any sudden change from deceleration to no deceleration. I guess most people don't care much about this, and they're okay with that little jerk when the car reaches 0 mph, but I like to minimize jerk when I'm driving.
On the other hand, entering my garage is slightly uphill. With creep, it's easy to control the brake pressure to maintain a constant 1 mph. Without creep, I struggle to find the perfect accelerator pressure for 1 mph, and the d(acceleration)/dt is not as low.