I think that's pretty much going against the vim mentality of offloading tasks to the appropriate tools.

This is the kind of thing I would expect to see in emacs.

That said, I can't imagine ever wanting to have a website render in my own editor, that's the kind of thing I'd like to use my target browser for.

For me the most common reason for rendering a web page in the editor is to have a side by side view of the markdown document I’m editing. I like using mark down to write basic documentation and tutorials and not having to have a render-> open in the browser step just makes that smoother. Yes I could have two windows side by side and yes I could have file events and watch for the markdown to be saved and kick off a render and kick off the browser refresh… but I can also just open a second pane in VSCode and let it do all of that for me.

But why not just have the browser in a split window? I don't think I've ever been able to do web dev without the browser open side by side.

Also, most markdown ssg's have hot-reloading.