Actually, how easy it is to be proficient with it has a direct effect on how lethal the weapon is. As for lethality of the round itself, 30 rounds of the equivalent energy of a 44 mag that can be fired effectively at close range as fast as you can pull the trigger is pretty damn lethal. Wouldn't you say?With an expanding bullet yes FMJ no...
But your statement of easy to use doesn’t equate to lethality