You’re still stuck in the browser sandbox (I prefer to think of it as a Browser-Plato’s-Cave in the context of whole nested systems). And you can’t escape the rectangular box imposed on you by the browser. …especially on mobile OSes: there is essentially zero system-integration by going that route because Apple and Google both need incentives to entice people into forking over that lovely 15-30%.

Things like Push notifications. Background activity. Guarantees about data persistence. First-class Home Screen app icon. Ability to directly share data with other native applications even if they don’t want to (to the extent it’s enabled by the platform’s native Share Activity). And to a lesser-extent: the ability to use native widgets for the best user-experience on that plstform. Too many SPAs fall into uncanny-valley when they start to look too similar to native widgets - and it’s off-putting.

And the fact that Fortnite still isn’t available as a PWA on iOS is telling… I was expecting them to launch an OnLive-like service rendered to a <canvas> over WebRTC by now… and worryingly this gives Apple a strong incentive to immediately halt any work on improving WebRTC in PWAs…