Stable coins are an independent branch of cryptocurrency. They are completely different from a decentralized cryptocurrency, however, it is very necessary for it, since they actually perform an auxiliary role. A special position among stable coins will be represented by national stable coins of states. It will be the digitized ordinary currency of these states and it will most likely be in demand, especially within this state. Many governments have already noted the positive aspects and advantages of stable state coins over conventional paper currencies. Therefore, stable coins will exist along with a decentralized cryptocurrency and will complement each other.