Yes bitcoin is taxable. Not by means of the government is taxing but I guess that the miners were the one who are asking for taxes. The confirmation is dependable on how much btc you spend. If you will spend the high amount in sending then the confirmation of your transaction will be fast.
I think it depends on the territory or country where you do business. I think some countries have already made plans or are implementing regulations to control and impose laws upon cryptocurrency transactions, and part of those imposed laws is taxation. I think this is inevitable since many countries have began to see the cryptocurrency market's real advantage, and as a legit market, it will not be surprising for government and countries to find ways to use it to their advantage.