There are still many problems in payment processing. One I can think of is acceptance. Merchant fees are way too high especially for physical payments. I can't pay using card at my barber or local convenience stores here. I suppose the reasoning is that card fees make it not worthwhile accepting for amounts below, say, £5-10 (inflated for microtransactions). Doesn't make sense for them to accept a big % loss in profits just to accept cards over cash.

If we're to become a cashless society extortionate merchant processing fees need to lower.