Indeed ! it is very useful. This protects the CPU. It limits its package temperature to 90°C in any case. The multiplying coefficient is adjusted consequently to achieve this goal. If you choose the first option, this package temperature will be limited to 100°C, which is very, very close to Tjmax. Another way to limit this temperature is to play with PL1/PL2 and to adjust the corresponding wattage in order not to exceed the desired temps.
Regards
sl91