I don't understand your comment about tools. Checkout is a git command (with an admittedly terrible ux). It is not part of git data model.

Like the article writer, I never myself use stash. I personally don't understand why they were added to the git ux. I think they needlessly make git more complex. Under the hood, a stash is just a commit anyway. You might retort that this is an implementation detail but as usual with Git, this leaks into the way it is used: if you ever lose a stash by mistake, you will have to go fish the corresponding commit in the reflog.