Unfortunately you seem to miss the point.
I am not here to say how great cryptocurrency is, although it can undoubtedly be extremely profitable (for better or worse), but to point out shaping it positively is important.
I guess your argument boils down to suppressing cryptocurrency being more viable than shaping its development positively, but history shows that many goods cannot be effectively suppressed and if people derive a benefit from it they will continue to use them, with all the disadvantage a black market brings (I am talking about the drug market).
Also you have to seem a rather idealistic conception of government, where even if people have to deal with the consequences of dysfunctional monetary system (eg Venezuela), it’s still preferable for people to suffer the consequences than to provide an alternative that is not sanctioned by the state.
I agree that aggregating suffering of different people is problematic. By necessity, it happens on a rather abstract level, divorced from the experiential. I would say that can lead to a certain impersonal approach which ignores the immediate reality of the human condition. Certainly we should be aware of how we truly experience the world.
However I think here we transcend ethics. We can’t hope to resolve deep issues of of suffering within ethics, because we are somewhat egocentric beings by nature. We see only through our eyes and feel our body. I don’t see that ethics really can adress that level meaningfully, it requires us to abstract from that existential reality.
For me the alternative is a more pragmatic ethical framework. It acknowledges we are not just ethical beings, but that ethics is important on an interpersonal level. From that point of view helping more people can be the right thing because we are aware we generally cannot truly resolve others suffering on an individual basis. So we are in effect helping the greater system of society or humanity. In that case there’s no problem helping a group instead of an individual. We are not trying to help “at the root”—which we may only be able to do for ourselves or perhaps people close to us—but contribute to society in a meaningful way. And on that level there’s a practical difference between helping one person or many.
In practice, for me that means I do take effective altruism into account, but also acknowledge its limitations. I’d say everyone does that implicity or explicity.