It's not, but by making it an App, it forces a user to remember to install it (good mindshare), it takes up space on the homepage (good, free advertising), it gets to track your device id and track you (or, partially track you on iOS), it gets to spam your notification bar with more free advertisements, it gets to hook into your Google Pay / Apple Pay cards automatically, and it forever gets to poll your exact GPS position, while also having easier access to various bluetooth stack stuff (tracking beacons, onboarding devices, etc)
Yes, ~80% of that can be done on the web too, but the app gives you effectively permanent-cookies and permanent-permissions, and people have more practice doing it there.
I don't like it at all, but I get why lots of companies write a webapp, and then shove it into a native app wrapper (whether via React Native, Cordova, Turbo Native, or equivilant). The benefits of the app wrapper and app store, outweigh the drawbacks, for many businesses.