First of all heat protection tape is used to protect against burns. But especially with 2-stroke exhaust systems it even has a performance-enhancing effect. Because 2-stroke exhaust systems are very sensitive to temperature fluctuations. But the power output is more constant at a constant temperature and can even be higher at higher temperatures.
This effect is often observed on the test bench where the first test shows less power than the second or third test with warm/hot exhaust.
This effect can also be observed in a less noticeable way with 4-stroke exhaust systems, but in a weaker form. Here, however, the heat protection band has an effect on fuel consumption, since less thermal energy has to be applied to heat the catalytic converter.
In addition, it also offers a small styling factor in some respects, as it can cover rusty exhaust pipes.