I don't think it says anything. When, in 1998, a younger Serena claimed she could take on any male player ranked around 200th Karsten Braash, then ranked 203, took both sisters on. Braash was thirty at the time, & no longer at the top of his game. At any rate he defeated both Serena & Venus in single sets.
I don't recall the year, but Martina Navratilova took on Bjorn Borg in Vegas when both were number one seeds. Borg won in straight sets.
Even prior to the Battle of the Sexes, Bobby Riggs, at mid-50, defeated Margaret Court when she was ranked number one in the world in the women's circuit.
Of course Williams can defeat most male players, most pros, all but 200 or 300 male players in the world. But at its highest level the men's game is much faster than the women's. So I don't see how there will ever be any equivalence between them at the pro level.
Too often the Battle of Sexes is taken to prove that women can defeat men at tennis. Of course they can, but only when grossly mismatched.