I mainly use them when I want something windowed but without tabs taking up space. Like monitoring my solar panels

Aesthetic and productivity. Which are good reasons.

Let’s say you access your company ERP system through a PWA, or the HR system. You want to alt tab back and forth to it like a regular app. You’re checking supplier data on the web and entering it on the system. It’s a lot easier to do so if your ERP is an app. But if it’s not available as a native app, PWA is a good alternative.