As a niche site, sure, it has users. It died as a competitive social network, which is the context that I'm responding to this article in, since it distinctly asks in the headline whether Tumblr is heading back to "the top".
So in context of Tumblr having a shot at being a top social network -- the actual history is a decline from being competitive with Facebook, to being a barely-unicorn, to basically selling for nothing and having no user growth. But again, if there's some evidence of an uptick I think it would be great to see. I'd much prefer Tumblr/Automattic over Facebook/Meta.