Cuy Sheffield, head of Visa encryption, recently tweeted that Bitcoin has a unique native bookkeeping unit called "sat", which currently represents 1/100 cents, while Bitcoin is $ 10,000. "Sat" is far from becoming mainstream, but it may already be the most well-known global bookkeeping unit representing a value of less than 1 cent. Since the payment amount may be only one cent, users will not be afraid to miss shopping or spending because the amount is too small. Even with high volatility, they may still make small payments without seeing much change in purchasing power. He believes that this is the main use of Bitcoin to replace fiat currencies.