In practice
Customer churn and revenue churn can move in different directions. Losing 20 small accounts is different from losing 1 large one, depending on which measure you use.
Churn isn't the opposite of growth. You can add customers faster than you lose them and still have a serious churn problem underneath.
Why it matters for product builders
Churn is late evidence. By the time someone cancels, the decision was often made much earlier and visible in how they used the product.
What changes in AI-first products
Churn itself hasn't changed. Detection has. A system can connect falling use, negative feedback and account risk before the cancellation arrives.
That creates more time to act. It doesn't guarantee the team notices the signal or chooses the right response.