You can seamlessly switch between keys without having to contact your bank and prove your identity. Obviously, that is more expensive, but worth it if you use them for something as important as your main bank. Some services allow you to associate two different keys with your account, which would allow you to keep your main key on your keyring and the backup key somewhere safer. So, for example, I use my USB + NFC key to login to certain sites on my laptop, and then the same sites on my iPhone by holding my key up to the back of the phone, triggering the NFC handshake. For example, a key that also includes NFC can be used with your smartphone.

Some models add genuinely useful features. The more expensive brands, such as Yubikey, may be more reliable.

If buying on the cheap end, maybe double-check the reviews to make sure they are robust. They are solid-state, so, should last for decades. You can use the same key for many other sites and purposes. 'USB security keys can be purchased at many online and trusted tech retailers and typically cost between 18-50 dollars' ! It goes on to say 'Just search for USB security key and make sure the key you choose is FIDO certified.

Bank of america security usb key