I mean if it wasn't for Clementine, Carlos would have had taken Sarah with everybody to look for Nick/Pete which would obviously not be good. Clementine is young like Sarah so she can give Sarah some good advice and what if Clementine wasn't there at the house at the time Carver came? Also what if Luke went by himself on the bridge? Who would of saved him? Bad people would probably hurt the group less because Clementine is a little girl and they would feel bad. Also...WHAT IF, CLEM WASN'T SUCH A BADASS!?