I am largely against the move to a “cashless society” for many reasons, not least because it excludes a lot of people who can’t get bank accounts/debit cards for whatever reason. Plus it leaves a trail – not ideal if you’re in an abusive relationship for example. It also makes it harder for charities to do bucket collections.
But, that said, I don’t think it’ll make a huge difference at GP. Indeed, it might make things quicker at the bar. Some big grounds have been using stadium cards for years where you can only pay for things with a top-up card (I think this doubles as your season ticket too), so it’s been coming.