If you own a keyboard or mouse with programmable buttons then you can make a case for macroing ninjutsu since external macros like that don't suffer from the minimum delays between actions that in game macros suffer from. Even then, however, lag still has a chance of messing external macros up so its still not always ideal. Mostly because if lag happens and you're used to using external macros then you will very likely be at a loss at how to execute them manually, or at least be much less reactive when doing it than you otherwise would be.