Chasing that asterisk:

This product is not currently available for residents of CT, DE, MA, NH, NJ, NY, PA, and RI. Rate for this product will be based on the residential zip code entered when account is opened within online application process. This is a variable-rate account....

The one makes me wonder what there is about this offer or those States that make it only spottily available. The big red flag for me, though, is that variable rate bit. Depending on how much it varies and how frequently, the same hassle you're thinking about for switching into that account is the same hassle that will keep folks from switching back out. The size and frequency of variations makes me wonder about how long that high rate will last and how far it will fall.

Also, I recall some while ago, warnings that turned out to be valid in too many cases, that banks that offered rates so much higher than the industry average were doing so because they were that desperate to attract capital (savings), and they were in trouble. Santander has been around for a long while and seems sound. It subsidiary Openbank not so much. I'm also paranoid (perhaps excessively so) about banks that exist only in the æther of the Internet.

There're also these two bits from their "Who's eligible:"

You must have an active U.S. mobile phone number
You must have a mobile device (smartphone or tablet) with face- or fingerprint-recognition capabilities, on which you can download and use the Openbank app —which you’ll set up your trusted mobile device.

For me, those are absolute deal breakers. I will have no financial connection via my cell phone.

Eric Hines