I'm considering downloading the smartphone app and activating the one-time password. I already have a very security password on my account and regularly scan for malware, so I don't really think it will be an issue, but better safe than sorry?
I do have concerns about my smartphone needing to be restored or something that would keep it from working, but sounds like I can set an emergency removal password if it came to that.
http://www.square-enix.com/na/account/otp/token.html
What are your thoughts? Just a paranoid enabler or a worth it?