190-200 ms ping has significant GCD clipping and, in XIV's case, tends also to have a high amount of missed commands/inputs. If you'd played at sub-90 ms for a while and then went back, trust me, it would indeed leave a very bitter taste to your gameplay. There is, however, virtually no difference once under 80 ms ping, as that point you're only being held back by internal cooldowns (animation times), which would be just as significant if you were somehow playing entirely client side / single-player.