I've actually started using BitCoin to pay for things recently and I was surprised to find out how easy and quick this actually is. This really is a no-bullshit electronic cash. No registration, no verification, no borders, quick and easy. I hope more goods and services are going to be offered for cryptocurrencies in future.
On the BTC blockchain, this can be a real problem. The best one can do is to hope that the BTC price doesn't swing more than the equivalent fee amount of a credit card transaction to make it worthwhile.
If you are willing to keep some of your crypto on an exchange (but remember, it is only really your crypto if you have the keys), you can try to automate the swap between BTC<-> stablecoin to reduce the exposure to price swings.
We've processed over $200k in orders with over $100k being in BTC and ETH payments since 2017. Crypto merchandise website.