I have three now and the UI to create more is still available. It's possible that clicking on it would fail (I don't want to needlessly waste card numbers), but I have definitely verified that replacing card details works: there is a button that lets you invalidate an existing card and create a new one.
In that sense it may be limited in the amount of cards you can have at once, but unlimited in the number of card details you could go through.
In that sense it may be limited in the amount of cards you can have at once, but unlimited in the number of card details you could go through.