The interesting thing is that assuming that there is a confounding variable that correlates with coffee consumption which is the real cause of the effect, the c

The interesting thing is that assuming that there is a confounding variable that correlates with coffee consumption which is the real cause of the effect, the correlation can still be useful in some contexts. For example, while that would mean that simply increasing coffee consumption wouldn't directly lower your risk of dementia and stroke, we can improve our assessment of the risk of a certain patient developing these conditions by asking whether they consume coffee. Even though the coffee isn't the cause, since it correlates with the cause, we still get information by doing that.