It's kind of funny as a web developer because for the longest time Apple seemed to be the one pushing the mobile web forward but now that web apps are reaching for feature parity with native, Apple's initial momentum seems to be ancient history.
It seems Apple still thinks of the mobile web as a content delivery platform rather than an application platform. Their proprietary additions (mostly CSS) largely focused on making things prettier, their rationale for opting out of standard features (e.g. autoplay) often only work under the assumption that the only use for those features would be in the context of traditional content pages.
You want an app? Develop for our walled garden we tightly control to offer our users the best possible experience. If you want it on the web, stick to creating content our users can consume in Mobile Safari, our app for reading websites.
Offline support? Only if you happen to live in the 99.99% of the world that doesn't have 24/7 perfect WiFi/4G coverage with unlimited data. If you've ever kept a page open in the background and wished the data would still be there when you come back, offline support could have helped with that.
The choice is not between a native and a web app. The choice is between a web app or no app. There are certainly apps that could cease developing platform specific native apps when PWAs are supported on iOS but the vast majority of apps that benefit from PWAs being supported universally are apps that simply would never be available as native apps (let alone native apps on more than one platform).