However, I am not sure they were really helping bitcoin's long term viability - other than allowing the Bitcoin millionaires to spend their coins. I suspect not enough of these people who got rich by holding bitcoins were using their bitcoins to justify having it as a payment method in the Microsoft store.
You aren't actually comparing the few seconds it takes to swipe your credit card to 60 minute Bitcoin confirmation I hope. It's about 'reversibility' of a transaction - for a Bitcoin transaction to propagate takes about the same time as a credit card swipe to propagate.
Edit: Wow why the downvotes? Seems like people here don't understand the first thing about how payments work in the real world. The funds are not 'confirmed' instantaneously. If someone walks into your store and pays you $1000 with a card, you can't say withdraw it in cash in 2 seconds.
It takes about the same time for a 0-confirmation Bitcoin transaction as an 'unconfirmed' card transaction.
Authorising the card is instantaneous and the funds can be settled into your account within a couple of days.
Sitting there waiting for confirmation for a bitcoin purchase for a videogame is like waiting for the credit card company to reassure you that the transaction is now irreversible.
That's the problem with fixed, deflationary currencies....no one wants to spend them.
As miners become less subsidized by block rewards and must rely more on fees for covering costs (and/or full blocks cause a spike in Bitcoin fees), it seems like the cost-per-transaction may swing in favor of fiat payment schemes.