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?
Both, some people gain millions from BTC and other Crypto investments, and some of people lost everything they had on the ICO bubble. So IMO it can make economy better and worse
Now ICOs are not exactly crypto currencies and the usage of these assets at a large scale will definitely improve economy. Even at present, anyone who invests in the right coin like bitcoin and then use it in the beneficial way, is able to improve his financial status. It is totally up to us, common people, whether we are willing to help ourselves by investing in bitcoin and altcoins or not.