The original intention behind Bitcoin, the first cryptocurrency, was to create an electronic cash system people could use in daily transactions. You technically can buy and sell things with it, but Bitcoin’s price fluctuates quickly, which makes it a poor fit for spending instead of cash. You could spend $50 worth of Bitcoin on something today that ends up being worth $20 tomorrow. It’s also not widely accepted as a form of payment yet, so you’ll have very limited purchasing power.