I like the ideas behind quantified self. This has not driven me to purchase an Apple Watch, but I am now on my second fitbit. I also use MyFitnessPal, RunKeeper, Mint, and Jenkins. These services provide low-friction visibility to otherwise obscured aspects of my life. The first step to self-improvement is to "know thyself."
Quantified self introduces an aspect of continuous monitoring to my life. I could view snapshots into my health every year at my physical or just kind of eyeball my health based on looking in the mirror, but neither of those provides the visibility to optimize my health. And auditing my finances every year at tax time is better than nothing, but that by itself will not lead to wealth.