... built X on top of Notion" startups ended up ... well, dead, or pivoted hard once Notion shipped the feature natively. Same story with email tools getting eaten by Gmail. Or calendar tools getting eaten by Google Calendar. Mailbrew, Sunrise, plenty of others the failure mode plays out the same way every time. The host doesn't even have to do it well. They just have to ship it. So surface-embed is a wedge in my opinion, not a strategy ...