Yes, it tells you nothing. It has no relationship to what's going on at the other end, which may well also be nothing.

It tells you that the app is actually doing something and your tap didn't land outside the button.

There’s at least one distinction I didn’t see in the article.

If a throbber is advanced by signals of progress or at least action, then it’s not useless and is arguably better than a progress bar that moves with unpredictable and uneven speed.

If a throbber is an animated gif displayed until something makes it go away, then it’s useless.