Is it worth it? I'm obviously biased, so my answer is to be taken with a grain of salt.
It never ceases to amaze me that you have to be so pedantic when saying something like this. I don't want to write a lengthy disclaimer explaining priors and terms - the entire point would drown in unnecessary prose. It obviously applies to normal families with normal parents with normal children. The love and affection from normal children to their normal parents are for all intents and purposes unconditional.
I've given tons of unconditional love as a child, I've seen it being received by many peers with kids, and hopefully will experience some of it with my own. Even if not, it is still very much worthy for me to have them.
Create life, an unique being which is a mix of you and your partner. Nothing else in life comes close to proper achievement in life, be it professional or personal (and I've achieved much more than was expected from me on all levels).
That's me (and many many people around us who already have them, lives are changed forever and for the better). If one doesn't want them, that's perfectly fine, find your own drive. But raising kids ain't some ancient, obsolete un-cool goal/achievement, in contrary.
Nobody said that you shouldn't want a kid, just that it is fine to not want one. Telling people who don't want kids that they are missing out on unconditional love is disingenuous.
I don't think anyone in this thread has made that claim. Just buy a dog if you want unconditional love. But it certainly is one major "benefit" of having children.
Not all reasons for having a large family are religious; some are just desire, of course, and some are indeed economically rational. That last is part of the reason, I believe, that birth rate drops as wealth increases, and is yet another reason to try to increase wealth for everyone.