I think it depends on what you except from the value traits. I haven't used them all yet, and only tested on one family but find they make a big difference.
I've been rotating around a little in my game and playing some families to level up parenting skills and set some kids on different paths, because I want my main legacy to have various and diverse friends. As I was rotating I was on a family with Nina Caliente and her twins and their stepdad. I decided to play around and cheated Nina to have irresponsibility trait, bad manners trait and argumentative.
It definitely works, she laughs when her kids burp or fart, she can encourage bad behaviors, and started an argument when her husband tried to discipline her kids. She'll also say and do things like, assert correctness, or Point out flaws autonomously and create conflict with her hubby. Her kids are both quickly falling into the red on manners, responbility and emotional control themselves.
The husband tries to parent them but the kids are taking forever to warm up even slightly to him. Her daughter is especially evil. She recently smashed the dollhouse then asked step dad to fix it only to smash it again. (She did this autonomously)
