>>bambax+(OP)
Businesses want you to use their app for a few reasons: it’s stickier because they can start sending you push notifications right away without even signing in/making an account, they get their logo right on your home screen, there are expedited login methods available like FaceID, they bypass most normal ad blocking so they can show users ads but also get much more reliable telemetry, they get access to APIs that allow them to request/slurp additional user data like your contacts list, persistent location services, and camera roll metadata, plus they can access a broader set of system APIs for fingerprinting purposes (even if against the ToS).
Then there’s a measurement element where app installs became an important KPI around the time ad blocking became more popular and interfered with detailed website engagement tracking, creating a self-fulfilling kind of thing.
On top of this I think another factor is that many websites are in terrible shape, super bloated by ten thousand tracking pixels and third party snippets added willy nilly by marketing teams using Tag Manager, so apps benefit from gatekeeping that bloat to a degree.