Worse, it encourages criminal organizations to hire juveniles to do the work for them. For example, I live in a country where preteens can't go to jail and unsurprisingly, they tend to be the foot-soldiers for drug syndicates. If they get caught, they just get sent to some center ran by social services or NGOs for a few weeks and then they can get out again.
Actually, that happens. Those kids begging on the street? Yup, some of those are working for syndicates. Sometimes you can actually catch them taking out the money from the small envelopes they hand out to people, so they can reused them.
Well, I guess begging on the streets is better than getting sold as a sex toy to some old geezer. Or you know, dead, after your internal organs have been harvested and sold. (The number of child organ donors is extremely small.)