Docs feedback: Building a Docker image with kaniko: debug image required?

Under Building a Docker image with kaniko, it says:

The kaniko debug image is recommended (gcr.io/kaniko-project/executor:debug) because it has a shell, and a shell is required for an image to be used with GitLab CI/CD.

Is it recommended or required? Will GitLab CI/CD fail if I don’t use the debug image?