Why? Because it will change the colour of the taskbar attending to the temperature of the CPU.
You can think it's nonsense, but sometimes, computers get hotter and hotter and this cute application can save you from a crash and the consequent problems.
Green for normal, yellow for caution and red for risk, so if you see that colour is not green, take care, clean the CPU and be careful.
You can change the temperature for each colour if you want and change colors too, but we think that preset settings are quite good.