And for years, it was our most requested feature, by far. We had instructions for how to pin the site to your home screen, and would explain to users how the website does everything an app can do. Still, constant requests for an app. Finally we relented and released one, and very quickly around half our mobile traffic moved to the app without us really trying to nudge people at all.
People just really like apps! I think it suits our mental model of different tools for different uses. We've also found that app users are much more engaged than website users, but of course much of that will be selection bias. Still, I can see how having your app on someone's home screen could provide a significant boost to retention, compared to a website they're liable to forget. For us now, that's the main benefit we see. Certainly don't use any additional data, though I won't argue that other companies don't.
I would say people really hate websites on mobile. The browsers are horrible, the pages are slow and oftentimes broken in some way. You get all these popups everywhere, ads are much more intrusive. It's just bad experience, so of course people would prefer app for something they use.
I avoid the browser on mobile as much as possible and I don't remember ever having a good time using it.
I've literally never had that problem. Firefox Mobile + uBlock Origin eliminates ads.