They tend to bury a lot, so I haven’t used them successfully. I mostly have tarantulas and some other predatory inverts so maybe for a reptile or something like that they would work.
It's not harmful but it might be not that tasty for some animals, just check it out ! There is no cockroach to my knowledge which is 'toxic' (male hissers could injure the mouth of a predator with sharp pronotum splinters but that's all).
My bearded dragons eat nearly any sort of animal, no matter how ugly the devensive secretion smells to me whereas my dogs prefere the non-smelling roaches/insects/spiders/rodents (yesss... on of my yorkies would kill for hissing cockroaches and mice, likes crunchy bugs and Tegenaria atrica -> a real dog knows what 'fresh food' means :lol: ).