Card-based credits allow the arcade operator to offer finer-grained pricing options than tokens that can only be spent in integer amounts. Whether that's a pro or a con is debatable, they can put less popular games on 'sale' to attract players to try them out, or they can gouge you on the hottest new title. It's also very much a way of obfuscating prices so you don't even realize how much you're spending. And are you really getting the best deal by loading your card with the maximum amount of credits at once so they give you a bonus, or is that just how they get you?

In the grand scheme of things though, I'm a lot less bothered by it than I am by the way modern arcades are mostly just gambling for kids now. At least most arcades still keep a few rhythm games in the back, actually I do love that arcade rhythm games are going through a sort of modern renaissance right now, but that's kinda just the only thing still worth going to an arcade for anymore.