That mechanism doesn't necessarily need to involve code being delivered directly from the same server the document is coming from, mind you. It could instead involve an out-of-band app store, where accessing a URL zero-installs a heavily-sandboxed plugin required to view it, and loads it into the browser. (Implementations of this: iOS App Clips; Sandstorm grains.) But those apps are usually still created by the same developer as the document anyway, so there's little difference between this out-of-band zero-install app approach, and having Turing-complete web documents. Either way, the developer of Boogle Maps can still mine bitcoin in the background while you have the map loaded.
It’s also a side effect of the demands of the attention economy fighting against Apple’s refusal to allow web notifications on iOS.
Basically, I don't see consistent patterns of good or bad between web and native apps to justify your comment that "apps are better at being apps than a web browser".
Most GUI apps, native or otherwise, get associated with a brand. Especially the good ones. I'd buy Ableton swag, I love the brand that much.
The VAST bulk of web apps are NOT browser version specific. It's largely only bespoke, internal corporate apps that are tied to one version of a browser.
The B2B productivity/collaboration app space — where you can expect that all your users are mainly using full PCs — is firmly all-in on in-browser web-apps, with their mobile experiences being second-class afterthoughts.