Creating Acceptance is super difficult.
Hence why crypto hasn't taken off with merchants. Because who's going to pay for merchants to change their point-of-sale systems to accept a new payment method.
Crypto is also a shit payment method though. Expensive and difficult to run and with high transaction fees. And if you use a chain with low transaction fees, there's no consensus on which chain that is (otherwise transaction fees would be high) so you have to support all of them. Then you might as well outsource the whole thing.
If the entirety of Europe comes up with a single system I think that'll be more than enough incentive for merchants to update their pos software to accept the new network. I hope that they are eventually so successful that merchants here in the US support them too. I'd love to stop using visa and mastercard.