Sureeeee. 300blk is a useless round unless you're running a suppressor, but since that has no way of happening in this state, I see it as useless. It fills a need that simply doesn't exist. A .45 carbine fits quite a few purposes
It has better ballistics then 7.62x39 out of a shorter barrel. Are you saying the AK-47 is a useless platform too?