You are of course right.

Users of software don’t care for the terms developers use to label their creations, “web app” or “web page” — it’s all the same to them. More importantly, they expect an identical behaviour from both. So when a web app can’t recreate its state from URL it’s breaking a fundamental web UI convention.

Another core UI convention that is often disregarded by web app developers is link click behaviour, i.e. you expect anything that performs a function of a link to behave as it normally would when you click on it with mouse’s middle button, or right click → context menu, or left click with modifier keys (cmd/ctrl, shift). Everyone got used to this and when the pattern is broken it is most annoying.

I work with a developer who thinks extremely highly of himself, and he seems to have never heard of this approach for SPA's.

Doesn’t necessarily mean he’s a bad developer; there are many frontend devs who see their job as pure programming. Which it is not. For frontend developer, an important part of the job is to know what a good design is and what concepts underlie it. Yet it’s hard to gain such knowledge without either designing or working closely with designers.

Not the parent, but Angular apps often involve rendering different views based on the URL fragment. This is intended to give you "bookmarkability". So for example instead of bookmarking something like this:

http://example.com/users/1234

it would be something like this:

http://example.com/#!/users/1234

Personally, I have found that for SPAs with centralized state, you can serialize the entire application state into the URL fragment. This means that no matter where the user is in the application, they can bookmark that URL and it would return them to exactly the same place that they were (authentication aside). The disadvantage is that the fragment doesn't necessarily "make sense" to the user, and the URL is too long to be conveniently remembered or retyped manually.

IIRC, in recent versions of the angular router, the second, #!-type urls are a fallback for legacy browsers (more precisely, ones that don't support the HTML5 history API). On modern browsers the url will look like your first one.

URLs are a big deal, and I absolutely loathe systems which actively sabotage likability on the web.

That said, it really was an offline app. We could've done it as a native Qt or .NET app. Even so, the standard AngularJS document fragment paths supported bookmarking and so on.

In the App-centric view, you don't bookmark anything. There are no bookmarks in desktop apps, for example. It's just weird that this 'app view' made it onto the web.

This “app view” is natural, because it’s less about bookmarking, and more about sharing — one of the key concepts behind the Web.

We used the Angular document fragment URLs, so it was possible to copy-paste and bookmark things.