When your bank goes under, the FDIC uses your money to pay creditors, same as Coinbase. You get a new account with money funded from the Deposit Insurance Fund.

When your bank goes under, the FDIC uses your money to pay creditors, same as Coinbase. You get a new account with money funded from the Deposit Insurance Fund. You have already paid for this insurance. You are also free to purchase insurance for your Coinbase deposits. There’s not a difference except one’s compulsory.