It's not just pennies, it's all coins. In a former life I worked in retail and almost nobody would fish around in their pockets for exact (or even near) change. They'd always hand me bills for their purchase even if they had just completed a transaction and had the coins in their pocket. That was in the 90's, and I still see it happening today, even though I'm no longer in the retail world.
I will never "tap" my debit card as long as I have any legal option. Everyone else can wait for me to exercise my consumer rights, by inputting my PIN, verifying the amount displayed on screen etc.
Courtesy may seem outdated to some, but it can occasionally come back to bite people. Being overly rude to waitstaff is something I’m concerned with around promotions because of how they might treat people inside the company. Without better information you extrapolate.