Originally Posted by ijgordon

This is not that uncommon of a design for hotels. Three I can think of off the top of my head that have a lobby above the ground floor accessed by separate elevators are the Westin Philadelphia, the W New York Times Square, and the Mandarin Oriental New York.
I think it's partly a function of security, but probably primarily a function of the real estate footprint; in many of these hotels there's no space for a full lobby reception on the ground floor because of restaurants, retail, or, in the case of the W-A LV, the lobby for the Residences.

I think this one is a little unique in that the lobby is on the top floor, and then you have to go down to your room, but actually once you're checked in, outside of late-night hours, you can change on the 3rd floor for the guest room elevators, so you don't have to go out of your way. IIRC after midnight, you have to go up to 23 and then down to the room, presumably for security purposes as there's no staff on 3 at that point.