Well, to put it another way, why would you devote time towards a hypothetical violent emission of kinetic force from an explosive device when you could more immediately benefit from removing an intelligent obstacle by applying force with a blunt object?

E.g. - why research a gun when you could brain someone with a big rock?

Seriously, not trying to be condescending here - if you could probably do a thing more effectively down the road with one path, why would you choose a more immediate path?

As OP said, detachability. If you have a venom gland, even if you have to go through a metal detector it probably won't be found.