I think bitcoin is a world currency not a private currency and because he does not hold by the government and does not have tax.. and i am agreed for this currency. so all people are wrong tell us bitcoin is a private currency.
I think no one said it was a private currency except if you have links. Even Satoshi did not claim it was a private after he invented and that is why we all enjoying it. Anyway it is true that it was world currency but only for investments but not for spending because not all people and not all nation welcome it.