Without understanding, you will be making decisions based on gut feeling, which is ok if you are Jobs, and not ok if you don’t have a magical vision for the product that will be a success.
I think of it as evolution. If you want to rely on luck - don’t track anything, let the natural selection work. If you want to control your destiny, think very hard about what you track and what you do when numbers change.
I saw both negligence of metrics and mindless obsession with useless ones, with the same results - frustration