Sounds like you're complaining about a lack of vision because they couldn't mix technologies from different years, or have the budget to make a phone as well as a camera...
But it does seem to be a clever idea, I'm imagining a phone that has surface contacts on its back, and a Go-Pro-sized camera module that you can attach to the phone (with precise magnets, so the surface contacts on both devices would connect both devices electronically as well) and be recognized as a peripheral for the phone.
But I guess if already have a pro camera, you don't want to need to slap your phone on it to get it to work.
That exists, the Sony QX100. Nobody bought it because it’s not quite as good as a real camera and it’s something you have to remember to bring with you.
The whole lag and connection issue shown in the video is probably why grandparent comment's idea hasn't taken off. Since no phones have surface contacts, maybe if the lens had a USB-C connection it'd be a lot better (but no closed-garden iPhone support, obviously).
But it does seem to be a clever idea, I'm imagining a phone that has surface contacts on its back, and a Go-Pro-sized camera module that you can attach to the phone (with precise magnets, so the surface contacts on both devices would connect both devices electronically as well) and be recognized as a peripheral for the phone.
But I guess if already have a pro camera, you don't want to need to slap your phone on it to get it to work.