Inflation and taxation are different things. Bitcoin is inflationary, not deflationary till 2140 after all 21million bitcoins mined by miners and all total supply exists. Now it is inflationary but its inflation rate is smaller than fiat currencies and the rate can not be changed by anyone, any government.

About taxation, governments can tax their citizens but do you think higher tax rate on Bitcoin makes it the same like fiat currencies. I don't think so, honestly because purchasing power of Bitcoin increases with time, like its value growth, so it can outweigh tax rate on Bitcoin investment and gain while you will not get any profit by holding fiat currencies.

Compares them in whatever criteria, Bitcoin is better than fiat currencies, not the same.