Most rental agencies will not require an international license. The advantage of having one is that it is a recognized translation of your local license. If you should have any problem, and I sincerely hope that does not happen, and do not have an international license you may be asked to provide an official translation of yours for the police or the insurance company. You might also find that the small print on the insurance requires them.
They don't cost much and are good to have in case of an emergency. Better to have and not need than need and not have.