No, how i understand is the GBT are like shares of the compagny, and based on how much money you invested( look images  in OP) you get a % of the money they will make from the betting site.
So the coin GBT really has nothing to do with the actual betting at all if i got it right, i also first thought the GBT was ment to replace the bitcoin/steam skins, but that kinda would not make sence.