Google Cloud Storage vs Redis / ElasticSearch
I don't know much about Redis/ElasticSearch, but GCS is not really a database-like solution, it is closer to a file storage solution.

If you're looking for database-like storage Google Cloud offers:


Cloud SQL
Cloud Bigtable
Cloud Datastore
Cloud Spanner


If you expect a modest app traffic or alternating high/low traffic it might be more cost-effective (and simpler) to have a Google App Engine app instead of a GCE-based solution.