does taking a certificate course in coursera look good for college admissions?

Answered

I disagree with the respondent's answer. Through the lens of an admissions officer, supplementing course rigor or showing evidence of intellectual vitality is more nuanced and ranked. In descending order from most impressive to least impressive I would rank it this way:

Most Impressive - Enrolling either in person or online college courses at a T50 school or a proxy MOOC that offers grades, and transcripts from a T50 school. So for example taking a real college course that is not a core requirement course like Differential Equations at a University or taking an Outlier.org course. It helps if you do it for credit, show an A grade for effort and be able to submit your transcript with your common application.

Impressive - Taking a DE enrollment college course at a community college to fulfill a core HS requirement course. So if your school doesn't offer AP Psychology perse but you can take an equivalent Psych course called Psych 101/102 at your community college and that CC has a DE program with your school. Then, getting an A in that will be a proxy for getting an A in AP Psychology.

Less impressive - taking an online course that is a self-studying AP course on eDx.org or where you have to do a certain amount of online lessons in a self-paced style and receive a grade and a certificate of accomplishment. Some of these courses are legit and taught by University partners like UCBerkeley or MIT, and some are not. These courses do not administer the actual AP Test. So you still have to register for those and take the test.

Less impressive - taking MOOC courses on eDx.org or Coursera that may have nothing to do with your intended major or fulfilling any core curriculum. But these show evidence of intellectual curiosity. So if you are interested in learning how to code in Python or learning about how AI the supply chain works, there are literally hundreds to choose from. Some are as short as 1 day or 1 week while others take a full 10 hours a week and go on for months to complete.

So whether taking a certificate Coursera course is going to be impressive or not really depends on what you are studying, the duration of the course, how it relates to your academic narrative or intellectual vitality, and your grade in the course.