[jmb99]

It does, doesn't it? Even if you stretch "web app" to mean "PWA" iOS supports them. And it definitely supports the literal definition of "web app" (i.e. loading a website in a browser that runs JS or whatever to perform its "app" functionality).

[fsflover]

According to this discussion, https://news.ycombinator.com/item?id=39563618, they don't behave in the same way or have all features.

E.g., For support, the Progressive Web Apps will still need to be built on WebKit, with all that entails.