These credits could then be used for things such as:
virtual-goods - bonus content in games or unlocking demos to allow unrestricted play
subscriptions to game-servers, where authentication would fail unless you paid a periodic subscription to said server. This would allow another way to make private game-servers which are still visible/promoted on the hub.
donating credits as incentives to boost desirable activity in the community - byond management could reward those who help new-developers, or hold competitions like Ludum Dare. An attractive cash-like prize with no 'real' cost to byond.
Revenue from this virtual economy would be split between byond and game developers in whatever percentages sound reasonable.
I'm also sort of hoping it would feed back into itself and promote/attract more professional(-ish) games to the platform, and hence attract more users.
This didn't work very well as internet commerce changed, and now certainly wouldn't work unless there were high thresholds for withdrawals.
I'd like to hear what Tom has to say about wrapping up BYONDimes.