0.005 GB is a competitive price until you bake in the total cost of ownership. In this case, it still makes better sense for us to use Google's Cloud Storage offerings for our 100TB of mp3 file storage since sending all those files results in outgoing bandwidth charges from our infrastructure.
Staying in the same cloud "ecosystem" (Google or AWS) allows for free incoming bandwidth and free bandwidth when transitioning between services (EC2 to S3 / Google Cloud Server / Cloud Storage). An important consideration.