GPG is a gimmick? What, you can crack encrypted messages now?
No. GPG is very useful for some applications.
It is completely unnecessary for a trust system and a stock exchange.
Why do you think no real stock exchanges use gpg?
What problem is it solving?
You never know, it might all change one day. the same way bitcoin is going to change the financial world, PGP could be a useful tool for it in the future too. What's with this pretention of knowing what will or wont be a success? They guy is experimenting a new kind of exchange, let him be, it's worth the experience I think.