This is indeed a good strategy, with big volume you may actually get some extra $ on interest. The problem is this system works on games bit less on app/music

This is indeed a good strategy, with big volume you may actually get some extra $ on interest. The problem is this system works on games bit less on app/music stores (i don't think many people actually use ItunesCard, GooglePlay Card and Steam Card), they just do a one shot payment every time they buy something