Capitalism (if done at least somewhat rightly) gives a ladder for anyone to climb up on their own, and it has helped to produce the prosperity that America has seen. Free trade works. What DOESN'T work is when the government steps in and tries to micro manage and equalize everything. If you want a prospering society, one of the key things you need is free markets with minimal government intervention.
Capitalism is generally a good system, but without some regulation and intervention of the government it lets people with worse opportunities just drown. People who come from poor families, groups that are often discriminated or people with disabilities have to be supported by governmental initiatives. It's only fair to compensate them what they did not get from birth (see Rawls for more elaboration on this topic). Once the society becomes willing to support vulnerable groups through private sector, the government can essentially let go.
Also, I see cryptocurrencies as the very implementation of libertarian capitalism, so I don't understand what it has to do with communism at all (how cryptos are in between).