There are only two reasons we need health insurance and neither of them apply to pooled mining. If not for those two reasons, health insurance would be a bad deal because you would pay more for insurance than you'd pay for care. Those reasons are the small risk that we will unexpectedly incur major health care expenses that we cannot afford and desperately need and the fact that insurance companies can use their market leverage to extract lower prices from providers. Because neither of those things apply to, for example, pet health insurance, it is pretty silly to buy pet health insurance. It's like a lottery in reverse where the odds are still against you.