I don’t think it’s any more of a “catch” than Apple Card is (I’m a cardholder). There’s no fees ever, even if you miss your minimum payment, and low interest rates there, too. My best guess as to why this works for Apple is a whole hell of a lot of CC transactions for apple products are processed through the Apple Store and this way they probably save on those fees. It’s also awfully nice to have a second CC number just for online txns and you can rotate that number out with one tap - so that probably also heavily reduces fraud.
My guess is that this also benefits Apple in a similar way - maybe by not having to transfer apple cashback around? But I’m guessing like Apple card this is one of those things where the extra “benefit” to the consumer is justified by whatever the benefit is to Apple.
I’ve been using a no-fee online-only bank since I came to the US, and while they’ve been rock-solid (and supported me before I had any credit here!) I’ve been thinking about what to do about a high-interest savings account - maybe this is an option now. We’ll see.