The only benefits I can see of "Apps", are the developer get's access to private information they really don't need.
Yeah, they get to be on the "App Store". But the "App Store" is a totally unnecessary concept introduced by Apple/Google so they could scrape a huge percentage in sales.
Web browsers have good (not perfect) sandboxing, costs no fees to "submit" and are accessible to everyone on every phone.
Sounds like a broken web app.
You are currently using a webapp that doesn't do this. It's called Hacker News, and it never asks me to login every time on my phone.
> when the app can just cache my authentication and FaceID me
Sounds like a broken login form.
Hacker News also allows me to login with Face ID on my phone, thanks to my password manager.
Optionally webapps can also provide Passkeys.