I happen to agree with you completely, so will most mechanics and the "Car Talk" guys (who could be more authoritative ). However, you'll find you just opened a can of worms because of all the people that are going to tell you its going to 1) Freeze up your brakes 2) warp your rotors and what not or half a dozen other issues.

Truth is, "P" isn't as secure as most people think and a backup is a great idea especially on a hill. On level ground it probably doesn't matter, but if you don't use it regularly the cable will rust and will freeze up so you won't have it when you do park on a hill.

But you aren't going to convince half the world of that....