Though I think credentials are important and add weight to a person's argument, I also think a well read person with life experience is just as qualified
The problem I see more and more of is the insistence on formal qualifications ahead of outright practical experience and ability. As an example, in my field, just about every position now stipulates that applicants must have dual qualifications - Electrical and Instrumentation; whereas previously most such positions were filled by persons like myself, i.e. licensed electricians with extensive instrument experience.
Despite having decades of experience in instrument work (including having managed a NATA registered Calibration Laboratory), someone like myself is now ruled out through not having that magic "Certificate IV" in instrumentation.
So........ having just completed the Advanced Diploma course in Electrical, the next one is going to have to be (at least) Cert. IV in Instrumentation!
Bill.