I've got worldwide health insurance through Cigna where there is no participation (I pay nothing) for any medical service, hospital, prescriptions, repatriation...50% for dental services.
Still, my company put it in the letter of offer that I must enrol into national health fund, regardless of other insurances I might have.
So, I am paying 45000Y each month for national health scheme although I will never ever use it (I prefer international hospitals should there be a need and no participation).