In my opinion not only Smart Contract can be possible as a Payment system - the cryptocurrency will have to offer. That's just one of the closest to possible possibilities. Cryptocurrency for me still is too early to be able to fully utilize its potential. Still have so many issues yet proving itself being useful either way.

As of now, we just have to accept how things operate. It may not be close to our ideals but atleast it has been a big impact to our economy so far.