That is not what I mean. Doing checks using your passport number is not good enough . It only proves that you someone used your passport number for a job. It doesn't prove it's you. It doesn't prove that you didn't swap with someone else (worker proxy). A digital id is a token fully controlled that opens compliance possibilities that are not possible or financially feasible by using just a passport number because the government does not control the passport numbers of everyone (especially those for which this policy is intended).
Think: the ability to verify that the id owner's face resembles the face of the id holder. The ability to check that the id owner address matches that of the id holder. The ability to flag employers containing id owner employees regularly failing those checks. The ability to do this regularly without previous notice to the id owner at national scale remotely or in person is a level of compliance you will never get even halfway with just using a passport number.
The driving license application page pulled up my photo from giving it my passport number. That photo of me proves that I am the owner of that passport. I recently gave my work my passport information to prove that I was legal to work there. If we need a new system to prove that I am legal to work there, then how was it good enough to use my passport for that?
Think: the ability to verify that the id owner's face resembles the face of the id holder. The ability to check that the id owner address matches that of the id holder. The ability to flag employers containing id owner employees regularly failing those checks. The ability to do this regularly without previous notice to the id owner at national scale remotely or in person is a level of compliance you will never get even halfway with just using a passport number.