@deepak_kv these are notes from a similar question we had in Support, I believe this still applies:
The need for a Profile dataset is because out of the box, the web SDK schema does capture the likes of user activity regions, consent and mobile push tokens are only collected when you have it. See additional resource at https://experienceleague.adobe.com/docs/platform-learn/implement-mobile-sdk/experience-cloud/journey-optimizer/journey-optimizer-push.html?lang=en#update-datastream-configuration
The orchestration layer in the Edge Network architecture manages the "user activity region" update via incremental profile updates, independent of the experience events. The fact is we do not add User Activity region information on Experience Events – the main use-case is for it to be available in attributes, therefore we issue the incremental profile.
Hope that helps!