I see nothing different, what's exactly the biggest difference if you pay tax using fiat and Bitcoin? I think you might end up paying 2x tax, first is your income tax and second is capital gains tax.
Technically people need to pay tax if they sold their coins at profit, it doesn't have to wait until Bitcoin can be used for paying tax.
I see however, in Switzerland, you don't any pay taxes if you made profit from selling cryptos.
Lets say you buy Bitcoin at 20k , and decide to sell at 70k. Not a single cents is taxable (article 16 paragraph 3 from the Swiss Direct Federal Tax Act)
Title 2 - Income tax
Chapter 1 Taxable income
Paragraph 3 :
"Capital gains realized on the disposal of private assets are not taxable."Selling is another word for to dispose.
Private assets can be cryptos, shares, cars, tv etc...
Only way a government can tax your profit you made from selling yor cryptos is if your are a independant and you are buying and selling cryptos as a living like a trader for example because the crypto are a in this case commercial assets and not private assets anymore.