I do not know what planet you are on, but if you go out and ask passers-by about cryptocurrency and their choice between cryptocurrency and regular money, more than half of them will say that they only heard about cryptocurrency, but they never used it, and those who faced it, will give very conflicting opinions.
Let's consider the situation if you want to buy something on the street with your hands or even in a small outlet. You need to constantly wear any technical device, such as a laptop or a smartphone with the received Internet. Carrying out transactions takes quite a long time, there may also arise along the way a number of technical issues. However, the most important thing is safety.  When they steal from you a smartphone, you will immediately have a lot of very intractable problems - a SIM card, electronic card, various secret addresses and access codes, and so on. You will not carry a piece of paper with you and manually enter private keys and other codes, they will most likely be in your smartphone. There are just a lot of problems. And here you just take out the cash money - and no problems. Everything is fast and clear. The cash money are stolen from the pocket of the bill, it does not matter, this is clearly not your last. Beauty.