Genuine question to understand - have you tried this approach to build or break any habit for yourself? What were the learnings from it - what worked and what didn't? And how did you tweak the approach for the next habit?

Short answer: yes, I have--walking. I think the main learnings were (a) have faith in absurdly small steps, repeated, and (b) my anxious brain is always looking for the slightest excuse to skip it. No real tweaks, except keep trying to make the step smaller.