Usage is easy to measure: clicks, sessions, messages. Change is much harder: a decision that used to take a week and now takes a day, a friction that disappears, a bias that narrows.
Adoption is a signal, not an outcome. A heavily used system may be changing nothing that matters; a lightly used one may be shifting exactly the behaviour that did.
Before launching a GenAI intervention, we define which behaviour we want to move and how we would recognise it. If we cannot describe the change, we are not yet ready to measure it.