Visual COBOL Build Tools for Windows is a component of Visual COBOL which offers the same compilation, build, and execution functionality as Visual COBOL but without the overhead of an IDE. Using Visual COBOL Build Tools for Windows in a container gives you much of the functionality of Visual COBOL but with a much smaller footprint that is well suited to working in containers.
The Docker demonstration to build the base image for Visual COBOL uses Visual COBOL Build Tools for Windows.