I think it teaches them time's worth so that as they grow up they do not get exploited by 'friends', whomever employs them, in-laws or whomever they do business with.
I notice that the ones that were raised in houses were they weren't, tend to get exploited much more by those, like the mother in law who leaves from her struggling daughter-in-law's home with a pantry haul every other month or takes unpaid work and overtime because their healthier coworkers wanted to leave tohome early.