Yeah, this whole thing seems a bit silly. You can't trust the webcam to be real or even functional.
And even if you could trust the entire website-to-webcam path end-to-end, you can't trust the image the hardware is reading. There's a reason that other face recognition systems like Windows Hello require that you have an IR camera, so that it knows it's not just looking at a photograph of a person.
It's just a cheap/easy biometric. Retina pattern or finger print are better biometrics, but generally require special purpose hardware for ease of use.
I would assume you wouldn't only use this tech to secure information. But I don't see really how this adds any security when software cams exist.
Plus you have other issues, like people like me who work in low light, or picture frames in the shot, etc.
Cool hobby project though.