Earlier quoted context omitted.
I believe their plan revolves around lending money and then charging interest on that (like typical banks). They already support overdrafts[1] on their app. [1]: https://monzo.com/features/overdrafts/
Right, but every other bank offers overdrafts and still don't make much money from current accounts. Additionally new regulations are coming in (in the UK) banning you from charging a daily overdraft charge [1], torpedoing it's one source of income, which doesn't jive with it's doubling in value in less than a year. [1] https://www.bbc.co.uk/news/business-48553193
Monzo has never had fixed overdraft fees, and can still charge a daily % interest rate as usual
Overdraft fees are also not their "one source of income"