I also like the Japanese Walking's focus on time versus number of steps because I can go for a walk with my parents and all three of our phones calculate different numbers that directly correlate with our gait. Mine is often half of theirs.
You sent me down a rabbit hole. In trying to track it down for myself I read a couple of others that I thought might be it, and was stunned by how obtuse these patents are.
What sort of leverage does this stuff provide? You mentioned "charge rent". What does that look like?