eggs are to live birth as batteries are to electricity from a wall socket.
eggs have a limited store of resources an embryo can use to grow, the same way a battery has a fixed and finite supply of charge to provide current to keep a piece of electronics operating.
a human egg would require a 9 month supply of food, and additional storage of host the waste produced during the gestation period. that make for one very, very big egg.
(for reference, a chicken egg only has to supply 21 days of resources for a chick to develop and hatch.)
We do grow in eggs. The egg is just inside the womb of a woman. This is due to the fact that, as "Dude" said, we would need to produce a huge egg. The only reason we don't lay the egg is so that the egg can get nutrients from the mother.
If your going to pick convenience, why don't we arrive in 'just add water' sachets? Or a stork, or grow like plants? Either because we evolved that way, or there's a deity with a particularly evil sense of humour.
There is difference between the birds and female human egg . The male human sperm fertilizes the egg And with in the female womb the natural process of human development begin . So it wont need hatching.
It would probably be more convenient. Your wife just sits on the egg all day while you work. Then it hatches.
