The certificate holders may be competing for the same jobs, though I really doubt they'd get one over PhD candidates unless there was something they had done su

The certificate holders may be competing for the same jobs, though I really doubt they'd get one over PhD candidates unless there was something they had done substantially at least as interesting as an ML/AI PhD holder, or I guess if the company absolutely can't find anyone with higher qualifications. And I think what I perceive as your doubts as to landing a job with one of these are probably founded. This is a way for the university to make a bunch of cash. As long as that happens, whether students get a related job or not is not important to the university except to help with marketing to prospects.