Both labels are correct—yours is simply more specific. If your bookstore had a “speculative fiction” corner, you’d see shelves filled with fantasy, paranormal, sci-fi, horror, alternative history, dystopian fiction, and plenty more. These genres all have one thing in common: They explore fantastical versions of reality. What if Abraham Lincoln hunted vampires? What if wizards roamed modern England? What if North America got nuked? What if humans colonized Mars? That writer used the umbrella term, as many agents and editors will do in their short bios. Some people dislike this term, criticizing those who use it as putting on airs. Others object to its occasional use as an alternate term for “science fiction” because that extends the sci-fi label beyond its purest definition as stories based on scientific facts and technology. I find “speculative fiction” a handy term to toss out when referring to fantastical stories in a general way.
I’ve seen that term lately, too. When I hear it, I don’t think science fiction, though, but anything that the writer is speculating about. I’ve even seen it applied to historical fiction, i.e. historical speculative fiction.
I think the rise of audience interest across the speculative fiction spectrum, rather than just in sci-fi or paranormal as was the case in the past, has brought this term into more frequent use.