[pluma]

You're mixing up cause and effect. "Ability to run without JS" is not a goal in itself. Nobody cares about users who disable JavaScript for the sake of disabling JavaScript and then complain when half the web stops working.

The reason websites should work without JS is that JS may fail to load (or worse: load incompletely or very slowly) over dodgy connections.

PWAs help by optimising repeat visits. This isn't exactly useful for something like news sites (where users typically visit individual articles at a time and may never come back for weeks/months) but can be immensely helpful for apps like Facebook where users will come back frequently.

PWAs also help by emphasising load performance. So even if the connection is slow, the app may still load quickly and reduce the time until the first meaningful paint and the time-to-interactive.

PWAs are orthogonal to making the app "work" without JS. You don't lose anything by making a regular "progressively enhanced" app a PWA. You also don't gain anything by making one that is not "progressively enhanced" a PWA.

However by using something like React to render the app you can use the same technology to render it on the server, delivering full content to the browser on the first paint. Where you take it from there is up to you and has nothing to do with PWAs or non.