Who wouldn’t want the chance to win some of their money back. I don’t think it constitutes gambling as you’re not risking anything - happy to be proven wrong though
I personally can’t see it happening because Monzo can’t be competitive enough on the products they provide. This is because they’re small fish in a big pond. Perhaps it could be an option at a later date when they’ve got the basics sorted.
I understand what you’re saying. It’s similar to what my energy supplier allows you to do each month when you submit a meter reading: