Early adopters are more engaged.

There's an inherent self-selection bias: they are by definition more engaged, more willing to try new things than the rest of the user population.

This means that the beginning engagement numbers of a feature will often look better than their numbers at scale.

The exception is if there's some kind of self-improving product quality that grows with use, e.g. a network effect

The question for a new feature's engagement is: what portion of the engagement is due to the self-selecting effect, and what portion is structurally due to the quality of the feature?