The tracker works across hardware wallets, exchanges, AND cold storage. Most people DCA on exchanges before moving to cold storage - tracking the full picture matters. Families can share and keep an eye on their cumulative stacking progress.
Fiat tracking serves a few purposes beyond selling: calculating collateral for Bitcoin-backed loans (get fiat without selling), tax reporting (required in most jurisdictions), and showing family/nocoiners their gains in terms they understand. The Power Law chart is really about visualizing where you stand on the adoption curve.
Fair questions.