Offering in game resources and favors to those people who can afford to pay the price has great potential to unbalance the game. Even to the point of passing on a unique residence from one player to the next.
Then again, I haven't been on the game. Maybe it isn't doing that. Maybe it's helped the game grow and expand. Maybe it's adding more flavor and fun to the game. I love the idea of unique residences, the places to stay always seemed some what bland. Hotel, apartment, nice apartment, whatever's up on blue. But just offering them to whoever has the money just doesn't feel right to me.