It is strange as something new as a cryptocurrency can be influenced by medieval philosophical and economics laws. However one of the most ancient economic laws explains why we have so few payments with cryptocurrencies.
It could not be only a technical problem, as we have many platforms specialized in crypto payment (TenX and Omisego, for example). Also, the demand and supply law would fill the lack of ways of payment, if there would be a great demand. It is something different, simply few people use crypto and altcoins for payments.
And here comes Sir Thomas Gresham. He was Chancellor of the Exchequer under Queen Elizabeth the second, in the XVI Century, and he is famous for the general law that "Bad money drives out good one".
This law means that when a coin is seen having an intrinsic value superior to another, it will not be used for normal payments, but will be saved in a coffin, and the devaluated, less precious coinage, will become used in everyday payments. It is something logic: if you have two coins, with the same face value, but one made of gold, and the other made of copper, you will spend the one in copper, and you'll keep the golden one.
In general, we can say that, given the same face value, the coin with the lesser marginal utility will be used for payments, while the other will be saved. So the "Bad money chase away the good one in common use".
And here come Bitcoin and the Altcoins: as they are seen having a marginal utility superior to their actual value, they are seen as means of investment, not as means of payments. So common people use them for saving, investing and speculating, not for making payments. They will be really successful only when they won't be seen so precious, and they will be used also for common, mundane payments.
PS This law is also known as Copernicus Law, as the first edition came from the famous astronomer,
