It's essentially a smartcard (certificate storage) in a more convenient form factor for most users, so you could use them to store your RSA keys - though person

It's essentially a smartcard (certificate storage) in a more convenient form factor for most users, so you could use them to store your RSA keys - though personally I would not trust them - but they are not FIDO/FIDO2 so they are almost useless in the context of the article.