Melio offers no protection against fraud. If your account is hacked you are just out the money. If you are a bookkeeper or accountant, you will be open to a professional liability claim.
Tip for consumers: Melio does not provide protection against fraud. If you use their service and get hacked you will just be out the money. Their position is that it is your own fault for getting hacked. If you are a bookkeeper or accountant using the service for a client - you are open to professional negligence claim because the poor quality of the service is well known.