Comment by necovek

A feature flag can still be fully on or fully off.

Why they might conflate A/B testing with gradual rollout is control over who gets the feature flag on and who doesn't.

In a sense, A/B testing is a variant of gradual rollout, where you've done it so you can see differences in feature "performance" (eg. funnel dashboards) vs just regular observability (app is not crashing yet).

Basically, a gradual rollout for the purposes of an A/B test.