FCC-ee Lessons from SuperKEKB

SuperKEKB has achieved significantly higher specific luminosity than its predecessor KEKB, and it has proven a much more sustainable machine. It has successfully demonstrated several key design elements of FCC-ee. The design luminosity has not yet been reached, however. This observation is often (mistakenly) used to put into question the reliability of the FCC-ee design luminosity. In this note we review the accomplishments, challenges and obstacles of SuperKEKB, and compare these with the FCC-ee design.