Emacs doesn't have "extensions", because every package can be used as a library or radically change the behavior not only Emacs itself but other packages too. Magit's parts been used in other packages - transient.el has evolved into a separate package; magit-section is used in packages like code-review.el, forge, notmuch; magit-git - low-level git interface functions used by packages like diff-hl, git-gutter, etc.; process handling abstraction used by packages that need async process management; etc.
VSCode extensions run in isolation, you can't directly call functions of one extension from another, you can only use what an extension explicitly exposes via its public API (if any). In comparison, Emacs users can freely incorporate Magit's internal commands into their configs, extend them and combine multiple packages seamlessly.
In Emacs, one could write a 5-line function that checks Magit's current branch, queries Projectile for project type, and then calls different Magit commands based on context. In VSCode, something like that would require formal APIs, message passing between extensions, and cooperation from all involved extension authors. In Emacs, you wouldn't even have to save the function on disk before trying it out.
For example, in my current VSCode + GitLens setup (must admit that I have a corporate license for GitKraken, which enables full GitLens functionality). I use these features 99% of the time.
1. Convenient diff/merge with character-level diffs and visual indication of moved code.
2. A graphical commit tree with filtering, searching, numerous hovers with lots of information, and buttons to quickly jump to all sorts of diffs.
3. Interactive rebase (GUI for selecting those pick/squash/reword etc.)
4. Editing new and existing commit messages in vscode, which allows me to use better commit message formatters, LanguageTool and LLM extensions for rewriting/paraphrasing.
When I see comments like "Magit is the only thing that keeps me from leaving Emacs," I honestly wonder what they're going to miss.
The "killer feature" is how it makes git feel like a natural extension of text editing rather than a separate tool. Other git UIs exist, but none integrate the "edit-review-commit" cycle as seamlessly. It's less about any single feature and more about how it transforms git from something you "switch to" into something that's just... there.
A huge part of what makes Magit special - it's not just a UI, it's a complete git API for Emacs - Magit is a library, not only I can easily extend Magit's own functionality, I can just call its functions, advice them, etc.
For example: If I want in my tab (there's tab-bar-mode in Emacs) some git-based info, I can easily do it. Or I can hook into magit-post-commit-hook to trigger custom actions. This composability is impossible with standalone git clients. You're not just using a git interface - you're programming with git as a first-class citizen in your editor. Other tools give you a UI; Magit gives you building blocks.
There are integrations in Emacs that Magit author and maintainers never even thought about initially. Like for example in Dired, where you'd be listing directories, you can mark some files and dirs, and stage those files or show the git log pertaining only marked items.
But again, it's not so much about features that already exist in Magit, but the way how one can easily extend things to add features that are not there - and there are tons of examples - note-taking workflows (where using Org-roam/Denote one can stage specific thoughts from their daily notes, creating atomic commits of ideas); literate devops (where you keep tf/ansible scripts in Org-mode src blocks and commit directly from the same document); academic writing (e.g., with LLM integration); time tracking (where people hook to magit-post-comit to automatically log time entries); config management (where you use magit's cherry-pick to selectively sync specific configs between work/personal machines), etc., etc.
Putting all Org-mode related features aside, since obviously Org-mode is much more Emacs-exclusive feature than Git support, here's what I see from your comments.
> If I want in my tab (there's tab-bar-mode in Emacs) some git-based info, I can easily do it.
I understand tab-bar is similar to tab bar in modern GUI editors - just a list of open files. Modern editors already mark dirty/staged files in the tab bar. Can you give an example of another information that one might want to add to each file?
> Like for example in Dired, where you'd be listing directories, you can mark some files and dirs, and stage those files
I assume Dired is some kind of file browser. While I appreciate the ability to integrate Magit with any file browser plugin, staging/unstaging files from the file tree sidebar is basic functionality of any editor with Git support. It's hard for me to imagine any life-changing improvement in this area.
> or show the git log pertaining only marked items.
Yes, that's neat. But IMO it's a very advanced feature that's used pretty rarely. Most of the time one wants to see either git log for current file or select some file in file tree in sidebar and see its log.
> Or I can hook into magit-post-commit-hook to trigger custom actions
You provided some examples for integration of Magit with note-taking. Advanced note-taking in emacs is a whole different world and I assume that person wanting to leave Emacs (but staying for Magit ;) will be ok with using some more mainstream note-taking software (like Obsidian etc.). So when using a code editor/IDE for its' original purpose - editing source code in some programming language, what would be a popular example of Magit hook that is not achievable with the existing Git hooks mechanism?
To clarify again my doubts, I think that someone who has mastered Elisp, maintains his own Emacs config and heavily customizes Emacs to his liking, would never consider moving to VScode or Jetbrains. However, all those Doom users evaluating to move to "mainstream" editors, who do only minor adjustments (like options, keybindings), do they get something substantial from Magit that they can't achieve in those editors?