The current setup is tedious and I can’t imagine a single user that would want every single email and contact logged in HubSpot. That’s insane.
I think you (HubSpot) are overcomplicating the UI on this. For now, why not just create an option (checkbox) to disable ALL emails and contacts from automatically pushing to HubSpot. Then, within the extension, create checkboxes and/or buttons that allow users to add specific conversation threads and contacts to HubSpot.
That would enable those of us who only want to see the most highly relevant data in our CRM.
Note: Salesforce does this.