VS Code extensions for language support are (usually) a combo of a language server plus VS Code extension code. Other editors using just the language server won't get the features implemented in the VS Code extension. So Emacs lsp-mode and a language server won't get you all the features that VS Code users enjoy.

For example, the Go language server (if enabled) in vscode-go is only responsible for hovers, definitions, references, and a few other things. Auto-imports, code lens for tests, helpful commands, coverage, etc., are all implemented in vscode-go's TypeScript extension code.

I recommend just trying VS Code for the languages you use in Emacs to see what you're missing. I bet a blog post about your experience would get to the front page of HN. :)

(One solution, of course, is to make it possible to write all of those things in a way that can be consumed by all editors. Check out https://github.com/sourcegraph/sourcegraph-extension-api to see our work to let you write any kind of editor extension in an editor-independent way (not just the language/code intelligence features). When this gets into beta, we'll feel comfortable updating this master plan to denote the progress toward the goals.)