1. Having better technical capabilities than traditional banks (they have apps, but they're usually limited and clunky).
2. Not having physical branches, and the associated costs.
> One reason that led Y Combinator to invest, Hariharan said, “was the traction with which they hit 2 million users in the U.K., with engagement metrics that almost look like a social network.”
It's a bank app. I can't speak for most people, but I don't open my bank app more than a couple of times a month; it's to pay my CC bill, and to make the occasional bank to bank transfer. If I'm spending a lot of time in the app, I'm probably encountering a problem of some kind.
I also can't link "app engagement" with revenue. Banks make money on mortgages, lines of credit and other financial products. I suppose daily logins allow them to advertise this heavily (my bank does it too, and I hate it), but to draw a line from A to B is a bit of a stretch.
Most people in the UK don't put regular spending on a Credit Card. Nearly everyone will use their Debit Card for day to day spending.
A lot of the traction it has got has been with the 18-30 age bracket who are wanting better budgeting tools than what larger banks have offered.
How much did my London Underground yesterday actually cost.
Send a Monzo request to a friend who said he'd pay for a taxi ride (he also has monzo, so I can just select his name and the amount, and all he has to do is press 'yes' when it pops up).
Check how much of my discretionary budget I had left to decide whether or not to buy a game.
Pay the window cleaner (bank transfer).