Don't forget that New Zealand has seen a very serious terrorist attack in 2019 where the terrorist Brenton Tarrant reportedly had used cryptocurrency to buy guns for the attack. So it's no wonder that New Zealand tax authorities are taking the matter seriously!
the government and the revenue office use these excuses to push their laws but it is never because of it. anybody who wants to do anything illegal would either use good old reliable cash or buy their crypto over the counter. those who use exchanges are traders and tax laws only affect them not the criminals.