I believe this was the DJ you were referring to :P
However, at some point during your time playing CoE you gain access to something so valuable that you no longer trust it in the hands of a bank. For example, let's say you're one of the rare few who discover the secret of becoming a Lich, and you've trapped your soul in a phylactery.
You wouldn't want to just put your phylactery in a bank box. The owners of the bank could recognize you as a Lich, illegally go into your bank box, find your phylactery and destroy it. No, that won't do.
You will find little teases from the devs on things like this and as you said talents, or magick even. But of all the things they will tease us with, how to become a Lich, and how to destroy a Lich are 2 things I am positive we will never know until we figure it out in game.
So as far as throwing your phylactery into the deep ocean... we don't know :D If Liches exist, and you figure out how to become one, you can risk the experiment of throwing the most important item you own into the ocean and hoping it doesn't get destroyed somehow. Be sure to let us know what happens!