You forgot to mention the "click on this one specific checkbox or your source code is now leaked to the entire internet forever" part. So actually, not that simple and potentially much much worse.
Except you also get a better history (assuming you write good commit messages), and it's all in the same folder.
You could also use git-send-email to make a mailing "list" with just yourself, and that way make it much easier to move between machines as you work. Or if you don't trust your email hosting provider, self host gitea or sourcehut (or have the option to later).
Finally, you also get the ability to better organize development with branches.
I don't even know git that well and came up with that off the top of my head.
Git doesn't require an internet connection. With git you can keep doing backups the same way and store the git repository in flash drives, Dropbox, Amazon Glacier, or anywhere you want. The main difference here is that you don't need one folder per version anymore.
Git has no checkboxes. It is purely command line. Are you talking about Github or Gitlab? I know Gitlab used to have this bug where you could easily accidentally give everyone access to all your repos.
Git != Github
Just using git on a local machine is nothing like this, unless there's something large I'm missing.