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The real hurdle to mass option is consumer protection. That is what made paypal big and until the average joe has confidence they can reclaim funds from an entity who didn't perform their side of the deal cryptocurriences will be backroom currency.
This can be achieved with an escrow service.
The downside is that you will have to pay fees and the vendor does not get the money instantaneously.
With the big flux of the exchange rate the later could be a problem.