There are third parties involved with exchanging cash, even though it might not be obvious. Central banks take part indirectly in these transactions, since they guarantee the value of the money.
The double spending problem is not a problem; it was solved already with BTC. You can always have your crypto on a physical drive, which kinda makes it like cash in the sense that you can have it in your hands like cash.
The double spending problem is not a problem; it was solved already with BTC. You can always have your crypto on a physical drive, which kinda makes it like cash in the sense that you can have it in your hands like cash.