I think a Monzo credit card should definitely have a points or cashback feature!
There’s only really Amex that do these in an abundance, but not everywhere accepts Amex so the only competitor really is Barclaycard 
It would be good if any cashback earned could automatically go into a savings pot, or the “credit card” pot where the payment due goes out of could have a competitive AER (a bit like the roundups on Chase) etc.