What then is the Pay Off of Psychometric Measures…?

In a word: Objectivity

Because of the scientific properties of psychometric tests, we can have confidence in the test results because they are:

⦁ Valid – they test what they claim to test
⦁ Reliable – they will produce consistent measures
⦁ Normative and objective – they compare candidate's results to the performance of others making up a norm group.