The guy who created that site started a thread here a few months ago. There was a long debate with him about why it's unsafe, but he might have deleted the thread, because I can't find it. Other people have come up with similar ideas: http://dkn255hz262ypmii.onion/index.php?topic=131274.msg897203#msg897203 You can read the extensive debate there and how we go into great detail explaining why it's a bad idea. The issue isn't whether it's a hidden service or a clearnet site. It's the fact that you have to trust a third party with your sensitive info. PGP is the safest option you have. Don't be lazy about your security.