Earlier quoted context omitted.
Somewhat of a meta-comment but I’m shocked at how many people are complaining about you not taking cash. Has anyone ever walked out of your coffee shop because they only had cash on them? I can’t remember the last time I paid or even saw someone pay cash for anything.
Remember: this is HN, where the bubble effect is strong. On Hacker News, everybody "knows" that Google Search is useless these days and that Amazon results are all counterfeit junk, even though in the real world I have never heard anyone bring this up and these services are still incredibly popular. It's the same thing with cash: I don't think I've seen anyone pay with cash in years. Even the old people at the grocer…
I'm not sure where you live. I work in a fast-food place on a college campus. While the students generally use their meal-plans to buy food, the moment we have a "parents' weekend" or similar event, we do a lot of cash.
It is generally poorer people (who don't have access to banks) who have to use cash (or resort to alternative banking systems that charge exorbitant fees).