I've yet to see any indication of IHG even thinking about this, which is where I normally stay.
However, I tried this at the Hilton in Tokyo about a year ago and wasn't all that impressed. It was buggy at best. Then last month at the Hyatt DFW, I tried it again with them and it worked flawlessly. I was able to check in on my phone, access my room, and check out, all without ever having to visit the front desk. I was very impressed with this and would enjoy this in the future.

Perhaps they should leave 1 card in the room before you check in for those times when you would be leaving your phone in the room?