It doesn't stop at 2. When I left Amazon about a decade ago there were at least half a dozen digital money services/products. Each vertical (retail, 3-p retail, Kindle, Gaming etc.,) all had their own stored-value service managing a slightly different version of the same digital money (gift-card, merchant balance, game coins). The feature sets overlapped ~95%. It may well turn out alright for the company but if you are an engineer or manager tasked with building yet another such service it's no fun at all.