This is a great idea but it has a flaw. The email that I would need sending would contain sensitive financial information and I'm not going to trust some unknow

This is a great idea but it has a flaw. The email that I would need sending would contain sensitive financial information and I'm not going to trust some unknown company with that data, regardless of the statement: "These emails are stored securely, so you can be sure that no-one except the intended recipient will ever read them." They need to solve that problem. The only way around this currently is to use two independent dead man switch services. One holds the key to an encrypted file, and the other email holds the location of the encrypted file. A similar concept is used on merchant ships. The captain holds the gun and the first engineer holds the ammunition.