Obviously one's enjoyment ultimately just depends on whether the experience is subjectively "smooth". But as it turns out, different people need different FPS levels to get that experience. Hence, if the topicstarter declares his experience as "smooth", that doesn't actually tell us anything about the game's performance on his machine, because we don't know whether he's one of those lucky people who only need 20 FPS for a smooth experience, or one of those unlucky people who need 60 FPS for a smooth experience.
Consequently, for any meaningful performance indication, objectively quantified data is simply a necessity, and has nothing to do with being "hung up on numbers".