I used to track sooo much health and fitness data... Then I realized it mostly wasn't actionable, or at least, I wasn't altering my decisions based on it. The answer was always, "more training." So I stopped.
I think they are only useful to runners, where weekly distance, speed and heart rate are massively useful. These are all very accurate things that can be captured, unlike weight resistance (swinging a kettlebell, dead lifting).
