She didn't even die in battle like other slayers. She was made into a freaking example as people watched it happened. And cheered. All these years of death, of killing, or saving lives, and for what? What the hell did it even matter?
And Faith went shortly after.
"I die September 2009. So Twilight must have his support from society before that. When did you first start to hear about him, before he gained support?" she asked, looking to Faith, she explained. "If we're going to live, we need to get enough power and hit before he becomes Humanity's Hero. Otherwise the world will just come after us anyway. They already hate us, we can't take him out when he's their savior." until they were all day. And Buffy had no desire to take over the world to make them all listen.
She just wanted to live.
They needed to find out where he was now. How to find him, who his support was. They needed every single detail they could get from Anya and Lauren in order to retrace his steps and put an end to it. She refused to die that way. She refused to let Willow die, to let Amy do this to Anya. She wouldn't let Dawn vanish.
She was taking this way to calmly. For now. She didn't know if that was a good thing or not.