SP was pretty useful learning T10 in i110, definitely made surviving Wild Charge > potential floor DoT ticks easier in final phase, also affects Prey. By now in i120+ it's not particularly useful anymore.

T11, it's nice for mechanics. Nerve Cloud was always survivable with only DK and full HP but SP can save people, quite a bit more useful for the auto-crit one though. Tanks get chunked pretty well in this turn too.

T12, aside from Revelation Phoenix isn't a particularly threatening boss, and the two things it'd be really nice for, Bennus and Flames of Rebirth, you can't put up SP for if you're MTing and/or in add phase. I could see this turn seeing the removal of SP before T11/13.

T13, SP should be up 100%. Even as you gear up it's really nice, it can make you survive Megaflare > tower without heals, and Gigaflare still requires good stuff until you approach i130. Plus the MT gets absolutely wrecked P1/P2, and Akhs are the deadliest sets of attacks in the game currently.