In a normal situation she is clearly not useless. She is one of the best healers the world has to offer and one of strongest physically. She is on par with Tsunade, who is a hokage.
Naruto, Sasuke, Kaguya, and Madara before are clearly on a different level of power. Compared to that level of power, even to Sasuke, Sakura seemed useless. But it wouldn't just be sakura, it would literally be everyone in the world who would seem useless in that situation other than Naruto and Sasuke. It wasn't until Obito's eyes came into play that Sakura stopped being useless in the current fight.