Fundamentally credentials make sense to me. If we were designing an employment system from scratch, some form of independent standards and certification would be difficult to pass up. It would aid accurately sorting skilled/trained people into appropriate areas of work.

I say this with no credentials whatsoever, so I'm not just trying to be part of the 'credentialist conspiracy'.

In practice our existing system just isn't fulfilling that purpose enough to justify the enormous amount of money being spent. Accurate signalling on knowledge/skill level has been lost in the noise of wealth/conformity signalling.