I kind of wonder about the mobile check-in also.

On recent stays, I'm not even puling out my card for the swipe, I just tell them to use the one on my MR profile and everything is fine. You still need a live person to get your key, offer you amenities (points, waters, SBux cert, etc.), so I'm not sure what the purpose of this is-unless we're headed towards a system where you can download keys on your phone. Then it would seem to make more sense.