Got a PS3 or PS4? That option may work for you if you already have one. Otherwise, yeah. I only really use steam for humble bundles when they come out. Also, have you tried installing FFXIV twice to 2 different locations then adding it in manually as a second one?

Never tried dual running things with steam before since I really don't care much for it. But it does have some good deals once in a blue moon

Your other option is purchase and create a second account on the Station. Log in one character send to alt, log out then into 2nd account retrieve the mail and send again. (old school way of doing things )