Tell me,why i need for pve debuffs,stunts and so on.
Well it's mainly for mob control.
Since u got no AoE ,unless you're on Kid Buu,the best strategies to hold mobs are stun, confusion,petrification etc...
It'll save u from getting stunned, cursed and ganged up by mobs who'll chain stun you ( and trust me it's annoying ). Furthermore, most bosses have guards and u can't solo them if u can't handle the guards... and so on.