It's less the pheromone thing for me, as cyberghostface said, it's not shown to be uncontrollable, and more the idea that they're some sort of destined pair. Even though it's certainly not gonna be a long term thing, it still just reads kind hacky to me, like if Superman hooked up with a never before mentioned Kryptonian woman who was also heroic and whatnot. It just seems way too neat, and is therefore kinda bland in concept.