What is the point of breeding your own lizards if you aren’t going to sell them?

I’m not talking specifically about species, but just in general. I’m just having trouble wrapping my head around breeding, giving birth to, feeding, watering, and maintaining a herd of your own, just to keep them, I just don’t get it. If you intend to share them with people, understand. If you’re not, I just don’t get it. Help me understand.