Fix-point temperature calibration is important because it establishes precise reference points for temperature measurement instruments. These fixed temperature values, like the freezing point of water (0°C) or the melting point of pure gallium (29.7646°C), serve as stable benchmarks for calibrating thermometers and other temperature-sensing devices. This calibration method ensures accurate temperature readings, maintains consistency in scientific experiments and industrial processes, and enhances confidence in the reliability of temperature measurements across various applications.