It depends on the sensors you need access to. An iOS PWA has access to Geolocation, Magnetometer, Accelerometer, Gyroscope, Camera, Audio, Apple Pay, etc.

Assuming the audio happens after user interaction within what iOS consiters "one event" and/or the camera is used within a safari tab and NOT "added to home screen" (once you do that getUserMedia does not work any more).

Until iOS gets their shit together and makes it so that adding a glorified bookmark doesn't remove features, it's not a real viable option.

Also bluetooth on Chrome.

That may be, but I tend to see soo many apps now days that just need basic rendering. I almost wish there was a revolution to go back to when the IOS app store just installed links to URLs. It's so terrible inside phonegap apps such that apps simply can't save my f-ing password! Instead of building out more mobile features to complete the progress made by HTML5 we keep going back to native apps for no reason. Yes I get that there is a certain class of apps that MUST be native, but I would argue the bulk of apps don't need this.

You're not wrong, but I see this becoming a smaller issue as time progresses. Browsers are adding features all the time and I can see this one being resolved soon as lots of devs are asking for it!

Yes, but half the apps just need to maintain state without logging in.