I believe the idea of this key that application itself can request a guided mode (vs guided mode triggered by a user or AppLock profile).
I believe application should use following API to request a guided mode:
void UIAccessibilityRequestGuidedAccessSession(BOOL enable, void(^completionHandler)(BOOL didSucceed));
In the case, if it's not on this list, this request will be rejected.
P.S. A device needs to be supervised.