SQL Server 2016 in a Windows container would be ideal when you want to:
Quickly create and start a set of SQL Server instances for development or testing.
Maximize density in test or production environments, especially in microservice architectures.
Isolate and control applications in a multi-tenant infrastructure.
Works on Windows only. Given that SQL Server on Linux is going to be a thing, I could see general release through Docker there as well, but we’ll see.