Some quick insights from a design perspective.
The main reason why we don’t want account numbers printed on the card is that at some point we might want to let you create multiple accounts and dynamically link the card to any of those accounts and things like that. So, the more “static” info we print on the card the worse.
Regarding the convenience of copying card details from the app. What we currently have in the app is still a very naive approach. @vuokko has recently been working on making it much much better, maybe she’s keen on sharing a small sneak peek? 