Perhaps you would know if this is more of a “crowd killer”, as I am thinking. 15 rounds full-auto from a plastic handgun sounds very uncontrollable. It seems it would only be effective for terrorist-style killing in a crowd, as was seen.
Along with these things, 30+ round magazines and 50 round drums (of dubious reliability) are aslo hoodrat status items. Videos I have seen, in the hands of competent shooters, these firearms cannot be controlled in an effective manner, they’re an area weapon.
Fully auto handguns have never been a practical item.