My concerns about a cashless society are the power it hands to a few oligopolistic credit card processors. Look at what happened to Pornhub. Regardless of whether you think Pornhub was in the wrong, it is striking that a business was cut off from global financial system by a small number of credit card companies. This was done without due process and under no countries laws. That should scare us at least a little.
How could a website function with cash payments at all?
I've only used my card with Uber a handful of times in 2016.