This is used to avoid misuse of insurance. For example, there are cases when people purchase insurance, knowing that they will be treated for an illness, and refuse insurance as soon as they recover.
It may seem that this is what insurance is for, but this is precisely the use, this is another product called "subscription" or "treatment discounts". Economically, it is much more expensive. Insurance is just for emergencies. It is thanks to this that it turns out to have such high amounts of insurance coverage for those who still get sick and a low price for you.