The decision to add SQL on top of S3 probably had a lot to do with a very common use case: people had structured data in S3 but no way to query it. However, it

The decision to add SQL on top of S3 probably had a lot to do with a very common use case: people had structured data in S3 but no way to query it. However, it is also very useful if the following two things are true: 1. You have a very large stream of incoming structured data that is mostly write-once-read-never, like logs. 2. Your query use cases are relatively simple and static. If those fit your use case, then S3 + parquet + Athena is very easy and very cheap.