I've seen many cases on mobile web pages where it tries to connect, hangs on a progress bar, my phone loses and regains signal during the process, it still doesn't finish loading, but a pull-to-refresh makes it load instantly.

That's an example where a timeout and retry would have fixed the problem. If it had been an API call behind an app, it would have hung indefinitely.

Some libraries sadly have their default timeouts set to infinite.