Passing off as a currency is really the wrong way to look at it. Can it be used as a currency? Yes, but as we all know is that we have deal with high fees on these transactions. Anything can be used a currency if the demand and there is value for it. Since it is finite in nature, it needs to be looked at in a similar fashion as other finite investment like gold or oil. Depending on demand and available product, market forces should regulate this. But in many ways, all these coins and tokens exists in a pure capitalistic environment. Subject to all the market forces both good and bad.