These certifications were absolutely useless when it came to getting me a job whenever I interviewed somewhere where they knew what they were doing. All they proved was that I was particularly good at studying and taking tests. This may be a useful skill in another career but in IT (the area of the certs) and even more in software (where I work now) memorizing rote knowledge is nigh-useless in the era of StackOverflow and Google.
Any sort of programming certification test would be gameable. A test that can be gamed isn't useful for hiring - once again, you're not proving they're a competent programmer, just that they're good at taking tests. No company you want to get hired at will use such a metric.
If it was possible to prove the quality of a coder via a certification test, we'd be out of a job. One of the key signs of a good programmer is their ability to expertly handle problems & situations they've never encountered before, which is (by definition) impossible via some sort of standardized test.
A certification might prove that I've memorized the parameters that get passed into the function in Array.prototype.map but it'll never tell me if someone can build software solutions to real-life problems.