Sakura is not a front line brawler.
She is a healer who has mastered anatomy, medicine and constant fine chakra control and herculean strength by the age of 16.
Now, skip the chakra control part and focus on the fact that she has basically become a doctor in 3 years as a teenager when most doctors have 12+years of study and do not begin practice until their late 20's and early 30's.
She is super duper duper smart and just because that cannot be contextualized by fireballs and ultra-violence means that our job as a reader is to imagine her role, not be spoon fed her role through the entertaining parts of the manga.
They worked together, Sasuke and Naruto went around for like 10 chapters trying to seal Kags and Sasuke acts like Kakashi and Sakura are a liability when in fact they turn out to be as crucial as our primary progatgonists.
The "losers" won this battle.
Without Sakura, Obito and Kakashi Sasuke would be dead in a desert and Naruto would be absorbed and the whole world would be turned into a giant pea pod of mutant warriors for some sort of intergalactic conquest.
Thanks so much to Sakura for helping save so many people with her medical ninjitsu, and punching Kags in her evil ass dome.
p.s.
on the Kags byakagun failing problem, if we remember the fight between neji and the sound ninja spider dude (sorry name is not in my brain..) we know that the byakagun has a blind spot, how odd that is exactly where she came from!
I wonder if Kakashi knows about the weakness of the byakagun and planned for it as part of his strategy?