That's 4% and I bet you pay another 4% to convert back to £ there's 8% you need to cover fees, then you have trade to buy alt currency and back to bitcoin to exchange into £, you lose 10% on transactions, means you need to be trading in and out of positions with at least 20% gains and more if you are trading small positions. This creates a speculative market and takes credibility away from the underlying securities giving credence to statements like what we just saw from Jamie Dimon. I don't think that he is right and continue to invest in cryptocurrency, but there are underlying problems that will need to worked out. Comparitevly I see these icos and a lot of the alt currency like penny stocks, lots of pump and not much substance. This is just my opinion and obviously means nothing