There's one added benefit, but its not clear who this accreted to: reduced credit card fees. Having one large charge is generally more efficient than many small charges, and if the savings are used to reduce fees or increase developer percentage then this is a good thing.
I would prefer the "wallet" method that steam uses. You require people put at least $5 in the wallet tied to their account. It's easy to remove the leftover balance because the first time you buy something over $5 it takes money from the wallet and charges you the rest leaving $0 in wallet.
