I thought it was a way for sims that you don't want to have a pregnancy to have a baby. Maybe you've head cannoned the character as cis male and don't feel that a pregnancy fits your story for them. Maybe you also don't want them to woohoo with a partner who can get pregnant, I can think of a few reasons for this. On the other hand, it could just be a way to accommodate players who don't want to deal with the annoyance of a pregnancy.
Personally, I'm willing to accept the lack of a pregnancy, although I would have preferred having it. But, like @Purple-Ink , I'm deeply disappointed that there's no lag time between ordering the baby and acquiring it. I would have strongly preferred a three day wait for the child to develop, a pregnancy period if you will, even if your active sim isn't experiencing that pregnancy first hand. I still think it's worth having, because my platonic life partner households can now have children together, in stead of just raising one or the other's children together. Also my sims who don't want a partner at all don't have to hook up with some random sim just to get the equivalent of a donor.