There are some fixed rotation that cannot make use of it or will change too much, the longer the fight goes, the worse it gets.
Blm for example will not benefit from a shorter cd of enochain, since he will use it whole cycle before refreshing.
Drg blood of the dragon normally allows for 3 geigoskul or however you write it, but with spear they change their normally static rotation that most of the drgs wont be able to fully utilize it.

The worst thing about spear is that you need to fill in at least 1 or more cds compared to a run without as well as consider burstphases, to make it truly effective, which makes it useless in short fights are dungeons where you get no benefit or arent able to utilize those extra seconds, on top of needing extreme raidawareness. To keep it short, yourself/smn, redraw/convert and if cant nin tank yolo.