This acceptance is based on a third party who accepts BTC and sends the government money in US dollars "BitPay".
this is the only way, imagine if they charged $1000 in bitcoin when the price of bitcoin is $10,000 and days later the price of bitcoin drops to $4000, at that time they get high losses. this high volatility of bitcoin do not allow bitcoin to be used as a means of payment. In the future when the market is too big I believe they will use bitcoin as a means of payment
is a good step and I hope that in the future they will accept payment in bitcoin without using third party