I've had most of the major banks and all of the major credit card networks as clients and they were actually quite well ensconced in the 21st Century. They even embraced stuff like REST, JSON and a public Internet. Of course, those were back end / security people as opposed to front office staff.
They were / are mostly a pleasure to work with. Although there was the first time I was in MC worldwide HQ and the only way to pay for anything in their cafeteria was cash or MasterCard. No MasterCard? No problem. They had a machine that would vend prepaid MC cards in the lobby.
"Priceless", as their competition used to say.