Biometric authentication is one that comes to mind. Facial recognition running locally on my own photo library would also be useful for organizing photos. A cloud-free local-only home automation system that can tell the difference between owners/housemates/guests and customize behavior accordingly would also be nice.
I'm looking into YOLO for this, but it's moreso to verify your selfie == image on document, and we want to avoid sending highly sensitive information to third party providers.
The current service we use, while accurate, costs 50 cents per verification...
Edit: reading through this thread, if the model isn't super massive, we could offer on-browser verification! 27MB is still a hefty download though.
