Great question, If your account gets compromised then they would have access to your data. However if you can ad an extra layer of security, then why not. It is true that if you switch to using a personal key on IDrive that it will wipe your data, so be sure to download everything first if you go this route. If you do not want to go through this process, you could opt to compress and password protect your financial documents using WinRar, 7-zip or WinZip with its own password. You can use this article on Komando.com that will go over how to do this.
Let us know if you have any other questions.