Well, what kind of KPI do you track then?

- new user sign up - new subscriptions - enlengthened subscriptions - mails send - overall interactions - testing of new marketing campaigns/channels (they do massive MVT, even fontsize&coloring)

just to make that clear: churn is tracked/written down for sure, but its not debated in a context of "is churn growing if more people are matching successful" - because in 99.9% of all cases people do not meet successful, so this metric is irrelevant