Adjustment is not slow, I have try it and the response is same as the other profiles, I can say it is completed within one or two seconds, so u need not to wait for too long.
i have a 9 yr old MB with this convinence feature, I used it every time I come out or get into my car, this function still works perfect. Unless u query about the durability of Tesla parts, it won't cause any unnessary wear.
I agree it is not a necessity but a convience feature, u can servive without it, u can even servive without an electrically adjusted chair. But since Model S is claimed to be and priced as a luxery car, it ought to have such a feature which is so common on cars of the other bland.