Why does every website ever want me to download and install their app, when the web is just as powerful an application platform for 90% of use cases? Especiall

Why does every website ever want me to download and install their app, when the web is just as powerful an application platform for 90% of use cases? Especially if the app is a really badly made bloated webview wrapper that doesn't work when you are offline and only provides a subset of the website's functionality.