IMO, this is a parable about meditation which tells of its many benefits, the greatest of which is Amrit, the elixir of life. Along the way, the asuras got disturbed in the churning when the apsaras appeared. As such, the gods obtained more benefits such as the appearances of Dhanvantari and Shri, the beautiful Goddess. Eventually, Vishnu awarded the amrit to the gods.
http://www.saivism.net/articles/churning.asp http://www.saivism.net/articles/churning.asp
