Why is a bitcoin any different to any other alternative currency then - in the UK there are small cooperatives reading their own currencies, Linden dollars etc in MMOs - why is bitcoin wrong?
Linden Dollars (along with WoW gold, EVE ISK), are owned by the respective developers. That database entry denoting your Titan isn't yours per se, you're just allowed to have it rendered as long as you abide by the terms of service.