> So as someone that work only with server side rendered stuff, you know, no JS on the browser and css loaded as one big blob, is there something useful for me here?

Yes, this is exactly about being able to use shadow dom (for its performance and modularity benefits) without any javascript running in client side

Isn't it similar to a generic idea like Object Oriented programming? It's a pattern that can work on a server or a client. Unless your server isn't using a DOM of course.

Do you realise that if you only work with server-side code, you can't use client-side code?

Yes? That is kinda my point?

It seems like Web Components want to take the place

Except web components are client side only.

Web Components are Custom Elements + Shadow DOM, and this makes half of that equation server-side. The other half works as a client-side hydration strategy until they churn out whatever Declarative Custom Elements would look like.

A sibling thread mentions performance improvements, so maybe?

I mean afaict rn the perf improvement need me to inject the style in the shadow dom element. So tons of small css, possibly with duplications and less compression, or css in style elements.

That... Can be useful but kinda problematic