My experience somewhat mirrors this. I've completed several Coursera courses on a variety of topics, but I don't advertise them on my LinkedIn or resume.

The reason I take the courses is because they are useful. If you put an effort into doing the labs, then you'll get something out of it. My approach is to try to write the solution to the problem based on the description, then compare with the solution provided to the lab. This ensure that I really learn the material from the labs. Every lab I've taken has provided enough time to get through it using this approach.

However, the labs offer the solution of the problems right in the description, and you get an infinite number of retries for the lab questions. So you can easily complete the entire course without doing any of the work.

So, the course material is designed to actually teach people who put in the effort, but the certificates themselves are a worthless signal of the amount of effort someone put into the class.