The idea was to create a Taser system that could be effective in the intermediate range (30-100 feet) where a regular handheld Taser could not reach, but from which thrown projectiles could still be a viable threat against someone.
Ultimately, the project was a commercial failure, primarily because of the cost of the cartridges. At something like $125 each, they were nearly five times the cost of regular Taser ammunition.
I read some can cause a lot of damage even if they just start to fly wrong
There was a big shift away from the term non-lethal to less-lethal or less than lethal because of this. Most every form of less-lethal force be it flash bangs, tasers, or even pepper spray can result in injury death if miss used.
Flashbangs can start fires, tasers can cause cardiac issues, and pepper spray can cause someone in a precarious position to hurt themselves (say stumble off a nearby ledge).
I remember reading about cops throwing a flash bang into a toddlers playpen and burning them.