This is also great parenting advice. Give your kid the feeling of having chosen to eat their vegetables, and they'll devour an entire plate of them.
Agreed. Our son always "decides" what he's having for dinner and what to do during the weekends, for example. Only he decides by choosing between 2-3 options we've selected in advance to match what we want the outcome to be. Similarly it's always bedtime before his actual intended bedtime so he can negotiate some extra time. It avoids so many conflicts when he smugly believes he has gotten exactly what he wanted out…
I don't like letting him "get one over" on bedtime. When he's old enough to know the difference, then what? You'll have to take away those wins. Same goes for basically everything else he'll want from you.
At least he'll (hopefully) negotiate well!