Because it is safer and more reliable than banknotes
Bitcoin is better than banknotes because bitcoin that has blockchain technology can record all transactions and still intact will not be lost or deleted. And bitcoin is more popular these days and bitcoin has easy ways to access and to transact, and since bitcoin itself are havingva faster transactions in terms of money exchange with a very low fees. And also, if we are just looking at this angle then we can tell that bitcoin is really better than banknotes but, if we look at accessibility such as the remote areas without electricity and internet access. On remote areas that had an shortage of sources in the third world countries then we can say that banknotes is better than bitcoin.