Probbaly because they're meant to be done in a large scale attack but this is the odd geoup having gor a hold of only one or twonshells that haven't been stored correctly and have no idea how to deploys them properly
I'm not asking why chemical weapons in general, I'm talking about the attacks in Syria at the moment.
For example the one above. Someone must have spent a fair amount of time making that barrel bomb, but it, and most of the other before it, did bugger all. I can only assume scare tactics.