Given the fact that most people are already maxed out on apps on their device with just things like facebook and youtube, you're going to be hard pressed to get people to install your app just to try it out. With a progressive web app if they like your app they can add it to their device home screen without installing via the app store and without using up space on their device. Also don't need to pay Apple $100 a ye…
If they really ever catch on, I could see where apple might require you to start hosting some kind of cross-signed cert or something that you can only get from Apple to install/use them.