Diflucan is for a specific types of fungal infections. If you don't have the ones that it is good for, it won't work. It also won't work for bacterial infections (or viral, though I think those are rare). It's nice in that it's taken orally (and normally one dose), also cis men can take it, there's a plus in my mind.
BTW, to clarify I got on vaginal estrogen not for dryness, because of recurrent infections that didn't clear up for anything. I think it's a sign of atrophy. Dryness isn't necessarily, tmk.
--Jay