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 think antifingerprinting means that browsers are constantly re-loading and rerendering tons and tons of resources. The web is much much slower than it could be in theory. If you have an siloed app then you don't need to worry about that and can reuse everything. You open a new tab and nearly everything displays instantly (except the different car or whatever you're displaying)
This would also decrease your network bandwidth load. So a win for you and your customers