FIRST OFF:
SE made SCing not important.. Go fight some IT mobs SC's shine there.
However SE capped XP and made IT mobs lose thier worth.. On HNM's SC's were good to use, maybe VNM's I haven't done many.

However when talking to an era of ppl where they know nothing but Abyssea...and their Idea of winning anything is to bring their fimped 10 rangers, or 10 blms or 10 bst and stuff magically just dies. And no ones allowed to melee cause it feed too much TP. SC's can't play play an significant part.

However I must digress that in low mans and being able to coordinate them isn't really that problematic. and like Monten said they do indeed add significantly to damage. Most DD's are arrogant/ignorant of mage Damage and more worried about their own on top of ur general backline mages being scared or ordered not to do anything besides cast stun. The result is Sc's are usually not preformed and then you have situations where mobs absorb SC's and what not it get's messy so ppl don't go out of their way to do em.. and if ur on console u cant see other's TP so that does help much at all.

However I will agree for the most part most things you fight do not need a SC, and is a hindrance, except in high defense/level corrected Situations...

When you fighting anything worth a grain of salt in low mans SC's can end a fight Quickly! Ppl talk alot about sacrificing damage as well. When almost every WS that makes light/darkness does near identical damage besides relic/emp/mythic weapons... Whenever I'm on a DD i don't prance around Firing off Ws's nonchalantly, Sc's can make up for lost dmg in a miss in a multi WS. and really missing out on 20 tp in order to gain a second Ws's worth of Damage is not a big loss, and if someone tellls you ur bad at math for that, then they are dumb.. cause 20TP for an extra 1k dmg is > 200 TP for that same dmg.. A 4000 Rudras storm outside Abyssea can close a 4000 Darkness? What is not to want to SC for that, cause I might lose out on 500 dmg from my scythe? I just gained 4000 for that 500 i missed out. No one will refer to these situations cause all they understand is *insert boring NM that a ninja and whm can prolly dual box*