Public transport becomes much better. You tap your card or phone and never bother with the hassle of a ticket ever again. You probably never realized just how much of a barrier the ticketing fuss was to public transport but all of a sudden you start using it a lot more.
Small conveniences based on cashless payment start appearing everywhere. I've noticed cashless vending machines for really rare use cases have started to appear where i suspect they'd be too low value/high maintainance if they required cash. I'd put electric scooters/bikes here too. Some things wouldn't work or be as successful without cashless systems. Lot's of these examples but i don't need to list them all out.
Taxation. You may argue this is a negative. I think it's a positive that it's harder to cheat the system. I like fairness. You can argue that there should be lower tax but i won't support any argument that it's OK for some to skip tax while others pay.
Safety. The tea lady at the station is now 100% cashless so simply can't be robbed (well kids might steal snacks off the cart but that's minor).
No more wallets. Australia has phone based drivers licenses and with no cash It's normal to carry a phone and nothing else. One less thing to carry and worry about.
I get that a cashless society would be worse under a totalitarian dictatorship than a cash based society under a totalitarian dictatorship. I'd rather work to avoid the totalitarian dictatorship part than the cashless part though.