to elaborate: this is a good feature because it provides an alternative to installing "official apps". majority of these being proprietary data vacuums sending all kinds of weird telemetry like what angle you hold your phone at to godknows who.

so for example instead of installing corporate apps, go to its website in the browser and "install" it as illustrated. You can use the mobile version of the website but it has an icon in your launcher and the browser interface is not available. It doesn't have the full amount of access to your device that a regular app does, but it has more than a website would. For example you can use "share" to send something to a PWA (if it was created properly). Whereas if you just have hexbear.net loaded up in a browser tab you can't "share" from another app that way. PWAs can even work offline.

https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Guides/What_is_a_progressive_web_app

and for the website to appear more app like to the user

Oh hell no