I think the divide is pretty clear.

If the app needs connectivity for data, and is just text/images/video, then yes, it should be a web app. e.g. news sites, social media, forums, etc. (It's a site, not an app).

If an app needs be able to work offline, on local files and data, then it should be native. e.g. office apps, image/video editors, maps, CAD, etc.

There's a grey area in between, but usually it's pretty obvious.