It's also a way for PMs who own apps to build habit-forming loops. If you download the app, you can send push notifications, deep link from email, etc. "Better experience" and all that, ultimately leading to more ad impressions or a purchases in-app.

And don’t forget tracking scripts too. Another huge reason.

Many users who use mobile adblockers will use one across the entire device (easy on rooted Android) instead of just a browser extension.