I'm not sure why you consider Robinhood to be a boutique brokerage or what having an app (as opposed to... physical locations?) has to do with anything.
They have over 6 million accounts, which is more than E*TRADE and within a factor of 2 of Charles Schwab or TD Ameritrade. And these brokerages apparently felt enough of a competitive threat that they all adopted Robinhood's commission-free model.
Regardless, even if you don't consider Robinhood to be a major brokerage, they clearly aspire to be one, so offering banking services makes perfect sense.
Guess I underestimated them based on their youth and company size. Didn’t know they had disrupted the market so quickly. If jumping into banking services is an industry convention, I suppose that goes to show that even a brokerage of Robinhood’s age and size must have the stability and temperament to provide reliable banking services that customers can trust despite their breakneck Silicon Valley startup ethos and lack of prior experience in checking.
Is it common for boutique brokerages to offer banking?