if too many people is using bitcoin then government will make rules to tax bitcoin transaction and maybe the government will banned bitcoin, but actually now we already pay bitcoin taxes, everytime i exchange my bitcoin in local exchanger they will charge few percent of my bitcoin
Yeah me too i don't really get the full amount of bitcoin im exchanging. Although i think it's more of transaction fee for the exchanger rather than tax 
bitcoin here is not that known yet so i don't think bitcoin would be taxed here for the next couple of years