The importance is to engage the core explosively when throwing the strike. It's not just combat sport, you will see the same in tennis, athletic throws, powerlifting
It doesn't have to turn into a yell, it can sound differently depending on the person.
It's not the yell that is the source of power, it's engaging the core explosively while throwing that brutally expells the air in the lungs, making the sound.
Focusing on yelling a sharp sound can help to learn how to engage the core explosively with teh right timing.