I carry cash when I know I'm going to be eating out. It has made it much less awkward because they are not spinning the Clover terminal around, or handing me the card terminal asking for a tip.
It's also just generally a good idea to carry cash. Electronic payments have too many failure modes, not the least of which are power and connectivity. (Currently posting this from a disaster zone which is thankfully still connected to the internet.)
Your senses of both etiquette and empathy are bizarre to me.
You cant think of a reason for people to pay taxes?