It basically is nothing more than a glorified shortcut. The installed app gets a custom load screen. It gets listed on the device installed apps list, and can be removed from there.
But there is nothing a PWA can do that a website can’t do. It’s all about Web APIs. Take push notifications (https://developer.mozilla.org/en-US/docs/Web/Progressive_web...): they make more sense for an (PW)app, but a simple website can do them too (if given permission).