However with a native app, you've chosen to install it, so you're at least partially interested in its notifications. With a website, you may just have browsed

However with a native app, you've chosen to install it, so you're at least partially interested in its notifications. With a website, you may just have browsed to it and have no intention of ever returning again. So the point of having to "install" the PWA to your home-screen mimics that first stage of intention. The key issue (as many others have noted) is that the "installation" step is still somewhat arcane.