I've found a pretty good use for a passkey. Docusign. About every 3 months I need to docusign something at work. The process involves logging in, changing your password, logging in again, opening the document, logging in to sign, logging in to finish. The only steps you get to skip if there's more than one document is the initial log on, and changing password. So with a passkey I just touch it a bunch of times and there's no password change.