Coral Acceletor is only needed if you run setup that does not have GPU or enough CPU. Spare laptop usually has enough power to handle AI detection, but RasPi doesn’t. I run mine in CPU at rack server.
Cameras own detections are limited in my experience, and it is much harder to integrate to anything else, like HomeAssistant for notification & automation
You can add IPS to port to add some security checking, but yes, in general port is never secure or unsecure.