Some illegal activity is commonly considered a moral good.
Cryptocurrency is used for illegal activity.
Therefore, cryptocurrency is a moral good.
^ This is a classic logical fallacy called a false syllogism. The archetypal example is "All men are mortal. Socrates is mortal. Therefore, all men are Socrates."
I assure you that all cryptocurrency is neither a moral good, nor is it Socrates.
Therefore, cryptocurrency can sometimes be used for moral good.
For example, anonymously supporting opposition in dictatorship regimes. Can you offer a better alternative than crypto?