YSK that while correlation does not imply causation, it does not mean that a correlation is irrelevant.

I see too many times on reddit where the phrase "correlation does not imply causation" is used incorrectly to shut down a discussion. While it is a true statement it is used in way to broad of context. So much of science IS done to find correlations, and correlations are extremely important to understand when circumstances do not allow you to find causation.

This article explains the concept very well. It brings up the example of how people who study addiction study methamphetamine use.

"We can't randomly give people drugs like methamphetamine as children and study their brain development to see how the stuff affects them, that would be unethical. So what we're left with is a study of what meth use (and use of other drugs) is associated with."