Then you have friends and family that don't have the same devices than you and are nice enough to want / try your app.
I think this is a perfect example... somewhere out there a genius and a grug are happily exercising together for the simple joy of doing so and feeling good in their bodies, and nearby is a midwit with the GDP of a small village worth of wearable electronics wondering where the joy has gone as he laments the 0.1% of VO2MAX he's dropped since his last gadget-run.