okay more serious answer i think they're qualitatively different modes of restraint. a child can register their immediate desire for independence more easily holding hands, and that independence can be granted more easily and revoked less easily, so its use can be better tailored to circumstances, and that lesson of self control can arrive quicker. if what is forbidden is always dictated by the parents, what does it matter to the child the reason beyond "because i said so"?

i'm just talking out my ass. i'm not an expert. i did used to be a child tho.