This proof of comments and is much harder to game than other systems. Somebody simply can't have a lot of sock puppets each with thousands of posts.
You are wrong. BTT is known for its market of Hero Member accounts.
No, I am right.
Sure there will be a few sock puppets, but there won't be any cases of 1 person is getting 5%.
To buy a BTT sock puppet isn't cheap. A person would be much better off just waiting for the inevitable dump after launch. We are talking about hundreds of people getting free coins for just responding to an email. There will be a big dump and anybody that is tricky enough to buy a hero account would be smart enough to know it would be much cheaper to just buy coins at launch.
To make a system where people can mine coins with CPU's is much easier gamed. I have 5 cpu's of i3 or higher at my disposal right now with 0% extra effort, but if I wanted to obtain 5 hero accounts just to get some of your free coins, that would be quite a task and an expensive one.
Proof of comments are are proof of work.