-Easier birth control: Make the egg into an omelette
-Relaxed child support laws: Requires deliberate decision to incubate the egg
-Clean packaged periods: Egg = No mess!
Although, there would be stories about partners hiding fertilized eggs: Instead of unplanned parenthood we would have unconsensual parenthood
There’s probably more nuances I am missing. But do discuss it in the comments.
The hard part of pushing out a baby is far less than 2/3 of the baby. Once you get past the shoulders they just slide out. And they are pretty slippery with all that amniotic fluid.