For the record, PWA are not the same thing as universal apps. They are simple websites with an extra JS execution thread called a service worker which allows for caching of code and content for off-line usage and push notifications. This has little to do with Electron or frameworks like React Native - which are famously bloated and slower than native apps.
On iOS you only have Safari webkit based browsers which limits access to PWA functionality found on all other platforms, thus favouring native iOS apps which have to be accepted by Apple's App Store.
On iOS you only have Safari webkit based browsers which limits access to PWA functionality found on all other platforms, thus favouring native iOS apps which have to be accepted by Apple's App Store.