If you're using a USB hardware token your knowledge of it is at least an order of magnitude better than the median user's. I know where my passkeys are stored, I don't know where my family member's passkeys are stored and neither do they. The same is true for most of my otherwise fairly technical co-workers.

The biggest issue with passkeys is that since most USB tokens that support them don't allow syncing the private key to a backup device you have to enroll ALL of them to every site that supports passkeys. This is annoying but it makes storing backups in secure offsite locations impractical.