When you have have Bitcoin in any wallet, it is like having your own bank on your own planet. It is not backed or controlled by any government and therefor cannot be taxed either as long as it is in Bitcoin. For now, you still exchange Bitcoin into FIAT when you want to use it, but like Japan since April 1, the time will come that you will not need to. You have to only look at taxes when you convert your bitcoin into FIAT.
In fact.... In the US, Bitcoin is a commodity asset if I am correct. You only pay capital gains tax once you convert it back to USD. In other countries it is also an asset. It is not seen as a currency. As far as I know, even in Japan, it is not a currency. It is only accepted as a form of payment.