you change diapers a alot! no, really a LOT.  snaps at night are a nuisance!  In the old days gowns like these were sold with a draw string cord at the bottom but those are consdered chocking hazards so now it's elastic at the bottom.
the only problem is that when you are carry the baby it rides up often you have to keep yanking it down. so during the day i would use a cotton t-shirt. (the reason for 4 stars not 5)

newborn babies cry for all sorts of reasons don't let uncomfortable clothing be one of the reasons.  forget fancy outfits until they are older like 3 months or more. even still i would use these elastic bottom gowns at nighttime for quick changes in the dark. why complicate things with those sleeper suit things if you don't have to?