Definitely worth an explore I think.
I think the reasons previously when it comes up are:
“In Ecosystem” variant of a credit card - bringing the same transparency to Credit as Monzo does for current account.
Bring Section 75 protections to a Monzo Product.
Traditional “Credit offers” - cashback / points / etc - although I think this wouldn’t be that strong of an offering in a Monzo product.
Better rates - like 0% purchases or other APR related benefits. (Though again I suspect Monzo wouldn’t be competitive)
I’m sure there are others, but mine is purely - would love a credit account flavour of Monzo. I suspect however it’s only really profitable for Monzo if you have users who are actively paying interest.