Tbh any MOOC that "needs only 2-4 hours a week" is, by design, an entry level course and taking more of those won't help you progress.

On the other hand, you shouldn't lump together and dismiss all MOOCs as there are plenty of more advanced ones that will definitely make a difference. For example, 90% of MIT classes such as Intro to Statistics https://www.edx.org/course/fundamentals-of-statistics or CMU Deep Learning http://deeplearning.cs.cmu.edu/