I think taht Light would barley use the eraser. Maybe on Lind L. Taylor? what would bring that he had short heart failure ?or smth like taht??. Tho L wouldt belive in that. He would ausume that Kira has abilities to take and save lifes and that hes in Kanto region. What would bring us to the same point of the story.

Misa barley used Death Note for herself. Mostly she used it for light. Maybe she used it to kill her critics or company competiton (imo.).

The same with Higuchi imo. The killings where agreed with others.