Certainly. But any business will have issues with cash and institutions. With banks, with customers, with the government, everyone. If you want there to be no friction ever for monetary transactions then be prepared to live in that world and make sure to express that opinion at the polls, there's not a ton banks and/or paypal can do on their own to make that world a reality without simply going rogue and abandoning all pretense of legality.

Also, re: minecraft it hasn't gotten much press but some people have had problems actually getting the game after they've paid, and in most examples the customer service they've gotten has been atrocious to non-existent. This doesn't just prevent people from logging into forums, it prevents anyone from playing on any public server and makes it a lot harder to even install the game or get updates (basically forcing people to pirate the game). Not that I'm saying Mojang should be raked over the coals for that, but it's not such a dissimilar situation.