We feed people with no jobs one way or another so I guess in some respects - it doesn't matter. However, the one we feed may be the only one there to look out for the children that might be there. Jail time might be better served as community time.
I think in the vast majority of cases jail time should be replaced with "community time", unless the person is dangerous or like in the cases of Conrad Black or Madoff a serious predator. "Warehousing" a person does no one any good. The punishment can be made just as miserable outside of jail (eg. cleaning Main St. with a toothbrush) while performing a needed function in the community.