it useful for T7 OT picking add for sure. For melee and caster add, if your timing on Voice is right after these add spawns, [ and if you got voice debuff or the caster add cast the stone thing.] then you will have to face away from the mob and cant build hate, then flash is your next best option(steal cyclone is not really an option since you need IB to take hit from Melee add.

it also good tool for grabbing hate on the newly spawn add as it does not require mob to be target.