[hunterb123]

> PWA is a whole different topic

No it's not, as hydration is used to improve the initial load times for PWAs. Afterwards PWAs will load offline first.

> faster load times is achieved by not using javascript, (pre-) rendering content on server and caching with CDN

Yes you can make sites not using JS and should in certain scenarios, that's not relevant here.

> this is how Wikipedia does it for the last 20(?) years and they sure won’t be changing that any time soon

Wikipedia is a web site, not a web app. It works really well as a site and thus uses technologies meant for web sites.

[ushakov]

> hydration is used to improve the initial load times for PWAs

this very sentence sounds absurd

how many websites out there need to work offline?

[hunterb123]

You didn't address my last points but I'll still address this comment.

> this very sentence sounds absurd

Which part? "hydration", "improve the initial load times", or "PWAs"?

Let me rephrase if you are confused. It renders a snapshot of the app on the server so when you first load the web app it's rendered already. Then the client picks it up from there. It's completely optional to do this.

> how many websites out there need to work offline?

Are you asking if it's useful to have access to information and entertainment offline? For me the answer is yes.

It depends what you are making, but yes I think you should strive to make things work offline if you can.

Also websites can work offline without CSR. That's not really what this is about.

Hydration is about improving initial load times of CSR. I really don't know how to simplify this further.