The problem with competency based training is that you can be deemed competent on the day under a particular set of circumstances, but there is no guarantee that you will perform to the same standard tomorrow, next week, after two months, or under a similar or different set of circumstances... Ask any instructor who has to sign their life away to send a student solo... It takes time to develop consistency under a variety of circumstances and the ability to apply knowledge from a quiver of previous experiences to new situations. This is one of the mysterious things that is hard to quantify (but valuable none the less) about experience and cannot be injected directly into a new comer. If nothing else, it increases the mental working capacity of the pilot operating under pressure before they reach task saturation in a complicated situation. This is why a 250 hour pilot can get out of their depth much quicker despite having good training and good SOPs.