While the bank use case makes a compelling argument, device attestation won't be used for just banks. It's going to be every god damned thing on the internet. Why? Because why the hell not, it further pushes the costs of doing business of banks/MSPs/email providers/cloud services onto the customer and assigns more of the liabilities.
It will also further the digital divide as there will be zero support for devices that fail attestation at any service requiring it. I used to think that the friction against this technology was overblown, but over the last eighteen months I've come to the conclusion that it is going to be a horrible privacy sucking nightmare wrapped in the gold foil of security.
I've been involved in tech a long, long time. The first thing I'm going to do when I retire is start chucking devices. I'm checking-out, none of this is proving to be worth the financial and privacy costs.