It helps me, when interviewing people (already past the HR screen), to make assumptions about what we don't need to talk about. I'll still do my checks on your knowledge to make sure you aren't just a cert collector who has no real hands-on knowledge, but it tells me that there are certain things I probably don't have to dig into.

Aside from that, I'd agree - it's a variable to plug into a dumb screening system to make you appear on the "good" list.

I’ve never seen any evidence of this happening in real life, but here on HN (and on Slashdot back when I read it) it’s common to see people insist that they would never hire anybody who _had_ any sort of certification. The reasoning usually goes something like “everybody I’ve met who had that certification was an idiot, so I can extrapolate that everybody who has it is also an idiot”.

Of course, there are people here who say the same about college degrees, too.

That's not an insignificant thing.