I think the ending has a very powerful meaning:

Seth has lost literally everything. He is no longer an angel; he is a mortal, suffering from pain, hunger and despair. He lost the love of his life. He has no job, no home, no money.

Yet he manages to pull himself out of mourning and depression, starts enjoying the simple things in life, and moves on, accepting his free-will choice of becoming a human.

Is that not powerful enough?