You are not that wrong, you are just missing one thing. Several characters have damage proc (Like SSR Kuroda Kanbei, SR Honganji "Voodoo is fucking OP in world boss" Kennyo and several other). These damage proc are not reduced by the damage multiplier of archer. Meaning if you use them in an artillery unit, you will do this damage proc x5 nearly each time, and it will do a fucking huge dps, even if the base damage is crap.