Many people wonder if they should use BigQuery or Bigtable. And the reason is the word “Big” that exists in both of them. It reminds me the Java and Javascript issue.
While these two services have a number of similarities, including "Big" in their names, they support very different use cases in your big data ecosystem.
https://cloud.google.com/blog/topics/developers-practitioners/bigtable-vs-bigquery-whats-differ
