Insurance is supposed to mean a contract, by which a company pays for large, unanticipated expenses in return for a premium: expenses like your house burning down, your car getting
stolen or a big medical bill.
Insurance is a bad idea for small, regular and predictable expenses. There are good reasons that your car insurance company doesn't add $100 per year to your premium and then cover oil changes, and that your health insurance doesn't charge $50 more per year and cover toothpaste.
You'd have to fill out mountains of paperwork, the oil-change and toothpaste markets would become much less competitive, and you'd end up spending more.
How did we get to this point? It all leads back to the elephant in the room: the tax deductibility of employerprovided group insurance.