Finally! Now if someone will build a browser that will add the missing push notifications feature to PWAs, web apps on iOS might have some semblance of parity with Android.
Till then, they're probably not going to do it.
The pros for bringing more features to PWAs: a small subset of users care, and an even a smaller subset of them care enough that they might leave the platform.
The cons: a direct competitor to the app store (imagine Hey as a PWA), undercutting their 30%. For the independent developer, sure, the app store may be great distribution, but I can imagine paying for your own marketing beats the 30% you lose to Apple.