This is pretty much what I meant. Even if the browser is what comes up, the fact is the user isn't interacting with the browser as a browser. They're interacting with their phone through an app (voice => search). They don't understand website URLs, or what search engines are doing. That makes it harder for them to return (engagement metrics!) than tapping the icon on their phone that opens up directly to the app.

It's also why so many websites try to offer push notifications or, back when it seemed like Apple wouldn't cripple it, the "add to home screen" or whatever CTA was that would set the website as an icon. Anything that gives the user a fast path back to engaging without having to deal with interacting with the browser itself is what PMs and marketing want.