A plastic card currently copes with all these tasks, although it also needs to be attached to the terminal, but it is better than cash. However, cryptocurrencies are not yet widespread enough to offer any great alternative to cash or plastic cards.
In some countries, there are already cardless payments accepted (mobile apps). In its usage, it is not so far away from the way we could use cryptos with rapid transaction speed. Well, it would be much faster for the merchant to get money, as card payment processors usually freeze the money for 1-7 business days and keep part of the balance of merchant frozen for even months for the potential case of a chargeback.
Here with cryptos, the transfer is final, can be almost instant and does not have card provider fees. If only volatility of cryptos would be lower...