That is true for now, however, there are a few bills in some states that are exploring the idea of accepting Bitcoin to pay for State taxes.1
[1] https://bitcoinmagazine.com/19418/bitcoin-friendly-bills-unv...
[1] https://bitcoinmagazine.com/19418/bitcoin-friendly-bills-unv...
2. States don't have their own currencies, so other than the ease of use of US Dollars, they really wouldn't care what you pay your taxes in, so long as they can use it.