Can a PWA do anything a regular app can do?
No.
But for the vast majority of apps that simply process generic data on the cloud, for example something like Uber, WhatsApp, etc, there's basically no difference between PWA and a native app. Actually many natives apps are simply a web view on a native wrapper. Note that you can even use a PWA offline after the initial download, if coded correctly.
But, if you start doing more interesting things like accessing the sensors, video processing, etc, then a PWA is more limited compared to a native app. The web view is just an extra layer that makes things a bit slower, and also there is some security added that doesn't allow access to some stuff.
For like 1% of the apps, you require it to be native for good results.