Hummmm...Ok, I've got at least 7 I can do easily, but another 10 after that would be a stretch -- what is there is Platinum that's worth going to the extra effort and expense?
Well, there's the Platinum arrival gift, but that is small change. I also seem to recall that the rules say that you get club access as a Gold only if you get upgraded to a club room, while Platinums will always get club access. In practice, however, my Gold level wife has gotten club access a number of times without the room upgrade.
The big thing, in my opinion, though, is the Platinum reservation guarantee. We have had a number of occasions when my wife was unable to book a room, but I was. Comes in particularly handy if there is some event in the area and hotel rooms are at a premium.