I think the point is that the wide rather sharp nose of a wadcutter by design cuts a bigger hole than a round nose, pointed SWC or non-expanding hollowpoint that all tend to slip through tissue. Soft lead expands pretty easily, as evidenced by the soft lead used in FBI load hollowpoints like the Remington R38S12. Granted, they are pushed by a +P charge.
My personal interest wadcutters for SD is based on their relatively ear-friendly nature, the fact that they cut a big hole and their lack of flash/recoil. Everything is a compromise, of course.