My first thought is that crypto is an apex technology, and pretty much requires every sort of modern technology to work. Not only that, but it actually can only exist as long as technology keeps expanding. Flaws in cryptographic algorithms, computational power to attack it, advancements needed in case someone breaks (it allow forgeries), etc. In my mind, cryptocurrency is another catalyst for technological growth. Now are people in China worse off because it was banned? Perhaps. And it is entirely possible that some form of cryptocurrency could be used for some sort of revolution. However, I think we also have to consider that once a technology becomes entrenched, it is hard to remove. Banks on the other hand have been around for a very long time and can exist with not much technology. So I think I would say it's probably better if cryptocurrency wasn't used at all in the world.