Spread betting also happens to be available as a tax free solution only in the UK. Since cfd and btc are international it allows for a tax free trading approach everywhere! I don't understand what you mean lower cost or execution, since the spreads we have are fixed, there are no commisions on our side and the execution time is fast. Also the part about trading against our clients does not really apply either. We cannot manipulate the market we can only make sure that our positions are hedged. If your preferences are different, regarding trading, it does not mean that the millions of people trading in forex could not get advantage of a "marriage" with btc!