Until the next day when you 1 million is now worth 840,000 and the the day after that it's worth 922,000 and then 740,000.... Bitcoin is not a practical way to store money. By all means speculate and invest, but treating it as a mean of savings is not realistic. Then there is the cut exchanges take, and the faff of their verification processes for large amounts transferred to FIAT. Then there︀ is a mater of where to deposit it, source of funds, capital gains tax etc.︁ Granted you can cash out small amounts very anonymously. But 1 million if you want︂ to liquidate it is no simple mater. I'm curious why you think it is viable?︃