Gonna defend the nunchuks, they're basically just a flail, you can hit with a lot of force without feeling recoil through your hand because of the chain, and nunchuks have roughly the length of a shortstaff at full range, but foldable because it's segmented.
If you actually wanted to fuck somebody up with nunckuks, there's no need for the elaborate moves they do in exhibition nunchuk competitions, you would just swing that shit at full extension towards somebody's head or legs. And, as somebody who has dicked around with practice nunchuks for fun, it's not hard to avoid hitting yourself if you keep it simple, follow Dusty Rhodes' rule "do not do shit you do not know how to do."
I'll recommend checking out a youtube called "Jesse Enkamp" who's a karate guy and explains the history of it in one of his videos, if anyone is interested. (this is not an endorsement of their other content, which I have not viewed or vetted)
EDIT: to answer the question, those self-defense spike things. Like yes you could hurt a person with them, but practically a crenelated flashlight does the same shit, but is also a flashlight, making it more practical and less embarrassing to carry with you.