I think taxing crypto only when you sell back into fiat has a problem, which is many people don't cash out into fiat. I can just leave it as USD or USDT or any currency on an Exchange, I can even privately sell my bitcoin into cash or goods and services. This negates taxes from BOTH parties which isn't fair to a normal tax payer.

In Australia, everyone with an income should pay tax, otherwise they can claim income benefits for people who don't make much money or make none. It isn't fair on normal tax payers to be supporting people with income but aren't taxed on it. Plus, tax helps keep the country running.

However, taxing crypto while you're buying/selling is dumb considering the volatility of crypto. This just isn't practical nor fair, as it benefits hodlers and fucks with day traders.

I think the best way is to be taxed when you BUY crypto into fiat AND taxed when you sell crypto back into fiat. This may be unpopular but I think it gets rid of all the problems I mentioned above.