The problem for decentralized cryptocurrency is still that it is very poorly used as a means of payment. So far, this is the most speculative asset, which is expected to grow in value over time. Therefore, states will use their digitized national currencies of central banks and, most likely, they will find support among the population. Paper money will gradually decrease in turnover, but it is also needed. I don't think we will be able to get rid of cash in the near future.