+ Being a parent is fun. Kids are super funny. Teaching them stuff is a treat, and seeing their interests emerge is a wonderful feeling. Assuming you love your spouse, you get to see this chimera of the best parts of you and your partner walking around in the world.
+ Kids are also familial and social glue. Even if you live a ways from parents, it's an easy excuse to stay in touch, a place to plan trips. One of the crazy things that as your kids grow they look and sound like different relatives. It's a cool experience.
+ Selfishly, it's nice knowing you'll have some influence on the world, no matter how small, after you pass.
I'm know some childless billionaires and honestly I wouldn't trade the decade-long headstart I've had with my daughter and her brother for all their worldly fun. Everything people say about parenting being the best thing you'll ever do is right – and they're underselling it.
FWIW, I understand the cynicism. You seem like someone who has suffered through tough times. I hope you find peace.