No. To the US Government, there is no other currency than the dollar. If you are a US Citizen, and working in the US, then you are using US Dollars. Everything else would be an asset. So if you are getting paid in BTC, that, to them, would be the same as you being paid in an equivalent amount of USD, then purchasing that much BTC. When you buy something using BTC, that would be the same as selling that amount of BTC, and then spending the USD.