I am very interested in hearing how you have been or intended to laundering your bitcoin profits? Even if you sell it locally for cash, how do you deposit that money into your banks without looking suspicious as to the origin of your money? Are you using it to buy a car or house? How do you explain to the IRS when you bought a $1 million house and/or $100,000 Tesla all in cash when you are only making $50,000/yr? I guess you must be running an Italian restaurant that has no paying customer as a front to launder your bitcoin money.. Or have rolls of hundreds under your mattress 
It is very similar to a person that has a Swiss bank account. The consumption of that person is a stimulus for the economy, so government will welcome you (A rich foreign customer). They will charge the car or house dealer for income tax, but not you
I can see many problems with taxation when merchants all accept bitcoin payment, since their bitcoin income are not traceable in current accounting system. One woman on the senate hearing session raised this question, but it seems so far no one have an idea how is that going to be handled