For example, I (used to) maintain a tool that is essentially a save file viewer, but must store some data for decryption of said files. It's an Electron app, but could work as a normal website for the most part as well. I got a prototype of that up and it stores the required data in local storage. I don't want to maintain and host a backend for it, and I'm not too hot on paying Apple's developer fee for it, either.
You may say it's a fringe use case, and it probably is, but it's very much legitimate. I don't know why they couldn't have made storage for longer than 7 days with an extra permission to be requested.
It is my own personal take that PWAs are more powerful than we give them credit and that they could be used for private apps without backends where you leverage the benefits of web distribution while keeping data private. Doing the native/hybrid app forces you into dealing with gatekeepers, distributing on the web does not.
Native applications also require acquisition of a Mac and a $99/year membership (iOS) and $25 (one-time fee for Google Play). A web application is mostly hosting costs which can be near free if you use the right cloud services.
I don't know of an alternative that will let me develop a small tool that will be free to develop and distribute, is not subject to restrictive store policies, works on desktop and mobile and is capable of things like accessing the device's camera and location when necessary.
I'm personally a fan of PWAs because they can't secretly write identifiers to my phone's SD card, they can't extract my contracts, they can't monitor my location in the background, etc. Sure, modern smartphone operating systems allow you to set up proper restrictions, but that puts the responsibility of making applications behave on me instead of on the phone.
Sure, native applications have their place (geofencing, native performance, file system access, system APIs) but in my opinion so do PWAs.