It seems to me that all of the reasons they provides are all reasons to get married. Especially raising a child, given the privileges that are afforded to married parents in a lot of places (especially in the case of adoption, or IVF using a stranger’s genetic material). Something doesn’t have to require marriage for the benefits of it to outweigh the cons for a specific situation.
The question seems to me to be kind of confusing. What alternative are you comparing it to? Some sort of local structure like domestic partnership?