A shotgun cartridge would be vastly less effective, and in many countries, even getting your hands on ammunition is difficult.

My objection is that it's mostly fright porn for drumming up mindshare. I don't think it's particularly compelling because a) imagining such systems is trivial, and b) there are already ways for us to achieve the same goal, so it's not even a novel threat.

But of course, that's just my opinion. Others obviously feel differently.