I once read that app users are seven times more profitable than web users. That easily answers the author's question about why a company would bother make an app when a web page is the natural fit for the use case.
I don't remember the source or methodology for that number, but I have no trouble believing it. An app gives the developer a foothold on the user's device. It can more easily send notifications, track the user's location, resist customization like ad blocking, and remain present on the user's device even when closed. It's easier to funnel users into profitable behavior with an app.
Companies wouldn't do this if a large fraction of users refused the app, but most users don't.
Apps bypass ad and tracking blockers too. They do have OS permissions as a potential roadblock, but most users just click "OK" on those prompts the first time when they install or open the app.
I mean, I don't know if that's a generation thing or what but as much as I'm comfortable using my phone, and ordering things in my phone's apps, when it's a website and I'm on mobile I always feel an urge to go to my desktop or laptop to check and do it there, I don't "trust" mobile websites as they always seem to give a limited set of information. Or at least that's the vibe I'm getting.
And in fact, a significant subset of users will pester you to make an app, even if your website can and does do everything an app could do.