-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 thing with eggs is that they would probably have to be huge. I guess that the egg would maybe have to be 10x the size of the finished baby (Idk for sure though) due to inefficiencies in the food metabolism. While for chickens, that’s not a problem because the babies are small, for humans it would be difficult.