What if all those big corporates and businesses starts using crypto as a mode of payment just to avoid tax which will cause a direct loss to the government which uses tax for the betterment of the country. This might not affect corrupt countries as it doesn't matter because tax money goes to politician's coffers but what about developed nations?
Just by having the fact that no country has ever regulated cryptocurrency massively yet, we can already say that all our assumptions are just theory coming from what we see and most of it are biased. We would usually say that it will give great advantage and a boost to the economy of a certain nation but things may turn out badly soon after the implementation of its regulation. Crypto is a decentralized currency which avoids any form of corruption but if the government would have a hold on it, things may go the way we don't want it to be.
If all of the countries and businesses will adopt crypto currencies and will be happy with it then keep in mind that the government will not want to pass any act which will disturb the businesses as if something affect the businesses of any country then it put a bad condition on that country and a disturbance is created for the law makers. They will regulate the crypto but will be in the favor of crypto.