The main advantage could be related to not leaving babies out in the street, mostly in countries where the weather is really harsh. And also, to avoid any kind of danger a baby can suffer just for being in the street. What is more, a mother who does not want that child can make sure, she is leaving him/her in good care and her identity will not be revealed or known.
On the other hand, the concept of 'bin' is not a proper term to use in this case. An unwanted baby is not trash, so he7she should not be associated with this idea. Maybe It should be wiser to resort to another term for the idea.
As regards sources, many people decide to leave their babies in a church or hospital or even hand him/her over a family they know. In some dramatic cases babies are abandoned in trash cans or put into a garbage bag anywhere.
