Unless you're paying with bitcoins, you can't just teleport money. You need to transfer it via third parties. Credit cards do this and take a ~3% cut. If 21 can

Unless you're paying with bitcoins, you can't just teleport money. You need to transfer it via third parties. Credit cards do this and take a ~3% cut. If 21 can get its chips into every household, they can take a much smaller cut, especially since the chance that a customer won't pay their bill is lower. You'd have to unplug your mining chips to avoid a bill, which would instantly notify 21. They can charge money to people's electricity bills and pay no fee. That is a competitive position.