Not that popular yet, but the Newspeak programming language runs entirely as a PWA, up to the IDE. Makes it really easy to set up. See https://github.com/newspeaklanguage/newspeak and https://groups.google.com/g/newspeaklanguage/c/s7c74c4QVvM

In India, most delivery apps have PWA variants which include tobacco products that aren't available in the mobile apps. These PWAs work fine and I don't see any difference in performance.

Youtube is probably one of the most popular

I think the Starbucks PWA is pretty good example from an implementation standpoint.

Facebook and Instagram are almost useable. Messenger.com is PITA.

X/twitter pretty ok.