Why do I need to pay Coinbase to protect my money!??

I was just on the Coinbase website and noticed they have different tiers of membership. Is it not weird that you need to pay for insurance for fraud? Shouldn't they have enough confidence in their systems to ensure that Fraud does not happen and if it does then they take care of it. At least that's how banks work. I understand they are not a bank but I feel like they are so large that at this point they should be able to provide that kind of confidence to their users. Am I missing something here