By monitoring brake caliper temperatures, you can make sure that the working range of the brake fluid has not been exceeded.  If the temperatures exceed the fluid, fluid vaporization can occur causing loss of the brake pedal.

For those running fixed, multi-piston calipers (Brembo GT, for example), recommended working temperature is < 200°C (392F), whereas the maximum acceptable working temperature is 220°C (428F);

Over 240°C (464F), the seals fitted into the calipers can be overheated and they will not guarantee the right performances of the caliper (sealing, roll back, fluid absorption,…);

If the caliper temperature goes over 240°C (464F), the dust seals and pressure seals should be refreshed.