Well it is simply that cash really works offline and it is the traditional way. This is the way of trading where we became dependent to it. Having a cash in real life is the traditional way of living, means that every people used that especially our elders. But bitcoin is the new money or new currency. But I think we need to cope in the future. And this is the future, this is bitcoin. The next generation of currency.
As for now cash is better than bitcoin because you can use cash anytime you want and it's so easy to bring with just your wallet.
If people are really want to use bitcoin in the future as for their daily needs such as riding: bus, train, plane, ship etc., then i think we need some kind of a bank for our bitcoin that can easily be used for our everyday needs.
Each has its own advantages over the other in some ways. There will always be a place for cash/paper money in our society because it's been there for decades it is traditionally used all over the world. We just can't suddenly use cash and use cryptocurrency, going cashless will only empower banks and will give us a hard time adjusting. On the other hand, bitcoin can be considered a digital asset where we can also treat it as money to use online.