My mental model does assume they must have plutonium in a meaningful quantity rather than just uranium for a dirty bomb to be remotely "effective" and I have no idea if that's even plausible. And if they do I'm not sure exactly what would lead to a dirty bomb over attempting an actual nuclear device.

But even a not very effective permutation of a dirty bomb seems like it could lead to headlines that look more "positive" for their leadership. (IE create outsized headlines.)