Only the man who crosses the river at night knows the value of the light of day.
For the majority of organizations, identity has no value unto itself. It is kept for the sake of driving business functions that ultimately benefit the identifiers as well as the identified. But without it, those business functions put you at great risk. Any useful tool in the wrong hands can do untold damage. Therefore you are obligated to validate the owner of those hands.
In the old, old days, your data was kept in one flat table, and the system generated an identification number for you. Anywhere else you showed up in the system, you were represented by that ...