in some bitcoin countries it's already applying taxes and that's great because bitcoin belongs to income. but there are still many countries that have not applied taxes because the country has not officially acknowledged bitcoin in the country.
Interesting, Bitcoin seems like an asset so id imagine only once you cash it out and its no longer 'anonymous' money it is traceable and must be declared.
Bitcoin and tax I think they didnt have a relation because once you earn bitcoin then you shouldnt forces to give tax etc thats why according to me there is no tax seems on bitcoin. Bitcoin is a digital currency and people all over the world invest and they didnt complaint about the features of bitcoin so if there will be tax on it then people didnt want to point out that.