The web can't access all the sensors on your phone -- at least not in their full glory. It might have trivial APIs like "take a picture", but it can't do anything specific to a piece of hardware, by definition. It can't control the camera's imaging pipeline (lighting, focus, preprocessing, etc.).
As a shortcut to understanding this, consider what hardware support something like ARKit [1] needs. Or consider whether you could write a multitrack audio recorder as a web app (no, because the web audio APIs aren't multitrack).
My point is that you need "general purpose computing" that is not the web for many things. The web is indeed open, but we also need our general purpose computers to be open. Android is better than nothing, but it's arguably not as open as a PC running Linux.
As a shortcut to understanding this, consider what hardware support something like ARKit [1] needs. Or consider whether you could write a multitrack audio recorder as a web app (no, because the web audio APIs aren't multitrack).
My point is that you need "general purpose computing" that is not the web for many things. The web is indeed open, but we also need our general purpose computers to be open. Android is better than nothing, but it's arguably not as open as a PC running Linux.
https://developer.apple.com/documentation/arkit/about_augmen...
The answer to the second question is also no.