I mean, I would use fzf if I were already in a terminal, but if I wanted a pop-up window, rofi is the right tool. Forking a terminal to run fzf seems a round-about way to solve this.
I don’t know what you’re asking, though. It sounds as if it does what you want, even if it isn’t the way I’d do it… are you asking because you want to make it easier for other people to use?