Edit
RIchard’s last comment & my reply below is related to subscriptions, rather than card not present transactions, see this post for more
That looks like a solid list of potential issues. But I don’t know how often they occur in the grand scheme of things. It sounds like a lot of the issues are caused by users not understanding how to use the cards correctly (though you could argue that this also means they’re too complex of course) & customer support teams not being aware of the product. Both could potentially be solved by widespread adoption & useage of the solution.
So I’ll defer to Monzo here, if they consider these potential problems & create the solution then great, if they decide it’s not worth the hassle, they’re well placed to make that call because it’ll cost Monzo if they get it wrong.
I completely agree with all of these points though -
I know that Monzo’s planning to implement all of the ideas that you’ve listed (apart from the first obviously, which is down to the merchants to implement) & they’ll be really useful.