All such weaponized technology carries the weight of danger, but de-weaponized technologies - which is what this represents to me - could mean some break-throughs, too. There are a lot of peaceful applications for a trebuchet.

And yes, it'd need training, but its not the training part of explosives training that I think needs to be rendered obsolete, but rather the explosives manufacture and distribution network, or in other words: peaceful applications for a trebuchet.