From answers given by some CS professors on Quora, just a cert from a MOOC means nothing to them if you are applying for PhD.
What they really care is if you have mastered the techniques you got from learning the MOOC.
I'm not sure Coursera is really aimed at already academically strong students trying to find a professor to accept them as a PhD student though.
Is the cert a step to proving you have mastered the techniques?
Perhaps doing something with the knowledge gained from the mooc. Like contributing to open source projects, side projects, etc.
For many Coursera courses, absolutely not. The cert just says that you're good at knowing where to look for the answers when you take the quizzes/tests. I'm sure there are some courses where this is less true, but most I've taken are simple "what do the provided notes or videos say the answer should be?"
So it is pretty much the same as "regular" college courses?