I love Monzo and have recently moved to use Monzo only. But they do need to make money to become a suistananble bank, I would happily pay a small fee per month to upgrade in some way and unlock extra features or maybe just get a supporter badge.
I know they probably plan to make money via the marketplace longer term though.
Shorter term the overdraft should bring some income 
Do we know when the overdraft is being made available to folk?
We’re in the process of rolling out overdrafts to all our customers in the next few weeks. Please bear with us over the coming weeks while we get everything up and running 
If you become eligible for an overdraft, we’ll send you a push notification in the app 