I think the main fact of being able to transfer GameCredits from game to game and not being "stuck" with that single game's currency is a sweetener no one has recognized yet.
how do the developers collect the gamecredits on their games then?
When someone purchases in-game items with GAME, the coins are registered in the system and paid out to the developer in a couple of days (developers are typically paid in 60 day intervals so this is a major improvement). Every developer has an account set up with GameCredits so the system is automatic.