It comes in really handy for helping players adjust their rotation for certain phases of fights. Take Sephirot EX for example. As a SMN my go-to opener is 2 fester 1 painflare. With a parser I was able to see that dropping that in favor of the 1 fester, 1 painflare, 1 energy drain opener yielded higher numbers due to the mechanics of the first phase.
They really do help. Its not all about epeen.