There's something to be said for distribution of work, too. I mean, my husband likes to do renovations and stuff on houses. He can do electrical work, plumbing, and carpentry. If he needs to get a project done in a certain time frame, he might hire somebody to do certain tasks. He'd hire cheap labor to do things like lift drywall, sweep, caulk, stuff like that, because it would cost him a lot more to hire somebody to do electrical work or plumbing. It doesn't make sense to run out of time and have to hire somebody at $100 to do some plumbing when he could do the plumbing himself and hire somebody at $10 an hour to do some nonskilled or less-skilled work. I'd imagine it's the same thing whether what you'll be doing is working on a more skilled aspect of a home renovation, or whether you'll be doing the job you earn $30/hour to do, or just reserving time to yourself or to spend with your children (which may be worth far more to you). Sometimes it's just worth hiring somebody else to do something because you have other ways you want to spend your time.
However, the benefit of having those skills is that you can make the choice. You can decide whether the size of the job and the time it will take is worth hiring somebody to do or whether you'd rather do it yourself. You can do it yourself when money is tight, and hire it out when it's not. You can do it yourself when you need it done urgently, tonight, rather than paying for a rush job. You can earn a bit extra in tough times by hiring yourself out on evenings or weekends as a handyman. Not only that, but you'll also be better-equipped to know what a job is worth, whether your handyman did a good job, whether he did the job the *right* way, and even to specify in a contract the way you want a job done. My husband got much better work done on a house because he knew enough about corners that builders take to specify what kind of materials he wanted, the quality of the job he required, etc. They knew that he knew what was up, so they were less likely to try to sneak in shoddy work or cheat him, because he'd know.
I think there are ultimately too many unknowns here, about exactly what the teen was doing, whether it was dangerous, whether it was hard, whether the teen got on-the-job training in useful skills or whether he was used as unskilled labor and didn't learn anything, etc. In terms of not getting paid, we should keep in mind that people used to *pay* to enter an apprenticeship where they would work for free but learn useful skills. Nowadays it's worth less to learn those skills, so people don't pay to become apprentices, but I could still see there being reasonable trade-offs. But I think it's hard to know without more details what the job entailed and what the teen gained, if anything, from it.