Maybe that is a mandatory work safety measure for all pilots and no one thought about excluding the Kamikaze?
Or maybe the helm will keep the cool headband in place?
Possibly they want the pilots to be safe from head-shots guns installed on enemy airplanes? So that they can fly safely to their destination and don't do down early.
Or maybe they have their radio speakers & microphone installed in the helmet?
The helmets protect them from head injuries while doing some manoeuvres that could cause them to hit their heads against the side of the cockpit ... not a very good kamikaze if you end up unconscious and crash before you reach your destination. Some helmets are also designed with oxygen masks that help the pilot breathe better at higher altitudes.
Lol mandatory work safety, wonder if they had some kind of healthcare plan