Trust me, native camera access is extremely important if you need to directly control focus (for example). We have web and mobile apps that scan ID images and our ability to capture high quality images on mobile native devices is 5x better.
You can still have native views that appear over the WebView for certain tasks. I think you can also provide your own rendering context for <canvas> elements, so you could roll your own <video> element for showing the current camera view. Either way, you can still have full native camera control without having a 100% native app.
