I also wouldn't call it below market rates. I'd call it "below the highest market rate" because rates for savings accounts vary and there isn't a standard "market rate".
Other reputable banks like Amex or Discover are only returning 3.75% right now.
https://www.cit.com/cit-bank/bank/savings/savings-connect-ac...
It is also part of First Citizens which is a decent sized institution:
Amex slightly lower, citizens access slightly higher.
Banks looking like they may lead to a more questionable experiences have even higher rates to offset higher chance of frustrations.
It's a common tactic to offer premium rates, and then drop the rate precipitously once they meet some quota N months later. Capital One did this circa 2020, for example.
That being said, if you're willing to play the game and monitor your monthly interest rate updates, go for it.
Otherwise, if you're a normal person who likes to ignore their HYSA account, it's prudent to go with people who are offering a rate closer to 4% (e.g. Marcus by GS is currently at 3.9%).
UFB, I note, does not offer a debit card.
4.15% is not the highest yield currently available, but it would put them fourth on this list[0] of ten, making them better than average even on that rarified list. This without fees or minimums, which would put them behind only Betterment, which is not a bank, but a brokerage account.
As always with an Apple offering, there are ways that some people under some circumstances can find better terms so long as they don't care about some of the benefits Apple is offering, but that's a very long way from "below current market rates," and comes from a company a lot of people are already trusting with their funds.
It's fine if you already have an account with UFB, carry on! And next month when it's a different company leading the pack, transfer. And the month after that, while Apple is still consistently in the top five.
0. https://www.investopedia.com/best-high-yield-savings-account...
The delta between, say, 4.55% and 4.8%, on the amounts I'm holding, may not be worth the potential extra headache of working with a lesser known bank. Introducing more risk (or just taking time to open more accounts) to earn, say, an extra $8/month... at some point becomes not worth it.