I think you made a critical error of being too generic? What field and what certs? If 90% of certs are junk the your takeaway is wrong because people are posting the wrong certs? What about industry? I didn't even know coders had certs but in infosec for example some certs hold a lot of weight.

I've been on the other side of an interview a few times and I can tell you, I will ask more specific and technical questions if you list a technical cert. I have a few certs but mostly to show my range of skills.

See, interviewers look at one thing I did on a past job or a few things I did because they need to be done and their takeaway is "this guy is more into such and such tech but we need someone who knows something else" but I list the certs to allow them to grill me and find out I actually know that shit.

Now, I have seen lazy-ass managers even on HN that blindly associate having certs with not having skills and to be honestI want nothing to do with such people or orgs that tolerate blatantly lazy managers who can't even delegate technical interviews to their subordinates but instead use gut feelings like this to make decisions. A person spends thousands of dollars on certs and their impression is that person is lame but someone half-starts a bunch of things and is a smooth talker and that's their man.

So, yeah, I guess it helps filter out bad employers just like it helps filter out bad employees. If you refuse to interview someone because they actually have a cert, yeah, that shit needs to be illegal.