A yubikey can only store one password, so you can't use it to log into accounts that take passwords, enter passwords to decrypt files and so forth. It does second factor auth, FIDO2 auth and things of that nature.

#Signet does store passwords (and other secrets like seed phrases, answers to security questions, and so forth).

The current firmware doesn't have the ability to sign nostr notes, but that could be added. Plus, it's open source so you don't need my permission to patch that feature in. 🙂

#Signet is an open source project, so we don't have a well funded marketing department. We have me, posting notes on nostr, trying to spread the good word that there are non-corporate, non-centralized, hardware based solutions to password management. ✊