That’s what Apple states, yes, but I suspect that it’s also used for calibrating the inner microphones of newer AirPods which is used for the “live eq” which works by listening the feedback inside the ear.
From my experience, Apple can sometimes “forget” to tell things.
Modern Apple gives you control over everything by hiding it in Accessibility settings. You can control almost everything about AirPods and give them custom EQ there. But it doesn't have that.
From my experience, Apple can sometimes “forget” to tell things.