Goldberg's answer "The 1Password Secret Key may not be the most user-friendly aspect of our human-centered design..." is unfortunately true.

We experienced a lack of understanding on the user side that this secret key needs to be printed and stored safely. It feels like a huge barrier for the adoption of 1Password for non-IT affine people.

This and other challenges led us to develop heylogin which does not require a master password and has no secret key that needs to be printed. Instead we generate cryptographic keys using the user's smartphone. For providing your desktop browser temporary access to passwords you simply confirm on your smartphone. This feels similar to modern SSO solutions but is technically a password manager.