The emphasis on functionality reflects the nature of the job. Software is generally like an iceberg in terms of time and complexity. The part you see is support

The emphasis on functionality reflects the nature of the job. Software is generally like an iceberg in terms of time and complexity. The part you see is supported by a much larger chunk that's generally invisible. When you're starting out, it makes sense to focus on the larger, supporting part. How important a GUI is depends on the nature of the program. A significant chunk of the world's businesses depend on apps that have no GUI while more or less everything consumer-facing has a GUI.