You're thinking of two-step verification [1]. I believe getting rid of the recovery key is part of the "more streamlined user experience" offered by two-factor

You're thinking of two-step verification [1]. I believe getting rid of the recovery key is part of the "more streamlined user experience" offered by two-factor authentication. [1] https://support.apple.com/kb/HT204152 https://support.apple.com/kb/HT204152