One thing is wrong with your analogy, your keep comparing the income in the amount of other "Currencies". Bitcoins has yet to be recognized as a currency by the government, so it is a commodity, not legal tender. So it would be more correct and better to compare it to lets say casino tokens. If you have $10,000 in casino tokens do you report that winnings to IRS, of course not, but as soon as that is converted to a recognized currency, then you report the winnings. That is how Bitcoins is treated and the only way it can be treated. Lets say I have BTC1000 obviously you can report bitcoins as bitcoins, so another area is the value is always changing so lets say one year I file on those BTC1000 and the mt gox price is $10 so I keep the bitcoins as bitcoins and pay taxes on $10,000. But next year those same coins are only worth $5, can i report I took a lost $5,000. Obvious answer is no but it should be yes cause it is commodity and having it's value determined by outside forces, of the market.
That isn't even close to true in the US.
If you earn income in ANYTHING it is taxable when the income is earned.For example lets say you make a website for me and I pay you in a 1 oz gold coin (hypothetical value at time of transaction $1,700)? What is your tax liability? By your logic nothing until you sell the coins. The reality is you have gained income (by IRS definition) of $1,700 at the point I give you the coins. When you sell the coins you may also incur a capital gain (or loss) but that is independent of the income. What about unique items? You build a luxury house for me and I pay you with a Rembrandt original valued at $2.8 million. Your tax liability? $2.8 million in income. It doesn't matter how you get paid, it is income, and it is taxable.
How about pure barter of services? Your make a website for your dentist and he fills in your cavity. Once again both of you gained taxable income. The amount taxed is the "fair market value" of the services.
Income is always taxed at the point it is earned. It doesn't need to be paid in dollars. If you receive anything of value for just about any reason it is taxable. For example say you win a car in a sweepstakes. Yup you owe taxes on the income value of the car. $50K car = $50K in income seen by the IRS; have your checkbook ready. Obviously your casino chip claim is false. One could simply use casino chips as a proxy (i.e. live in Vegas and pay all your bills by casino chips) and never incur any taxes on casino winnings for life.
More on IRS & Barter:
http://www.forbes.com/2009/11/11/irs-tax-barter-exchange-income-personal-finance-wood.htmlThe IRS starts with a down-home definition. Bartering is trading one product or service for another, whether informally and one-on-one or with multiple parties in a commercial setting. It has a storied, even ancient tradition. "Our ancestors may have exchanged eggs for corn," explains the IRS, but "today you can barter computer services for auto repair." The IRS also lists plumbing services for dental work. You name the swap, the IRS wants to tax it.
Wherever it [barter] arises, it is income to both sides, just like cash, according to the IRS. That means each side must report the fair market value of the item or services received on their tax returns.
http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Bartering-Tax-CenterFor a second think about it this way. If income wasn't taxed until converted to dollars it would be trivially easy to never pay any taxes ever for your entire life by never converting to USD. i.e. I trade you 1000 shares of xyz inc for 20 oz of gold. I then take the 20 oz of gold and trade them for a years worth of dedicated server hosting. The webhosting company trades the 20oz of gold for food at the local grocer to feed his family for the next two years. Nobody has any income? Nobody has any taxes? Really does it even seem plausible the IRS didn't notice this massive loophole.
The only time that taxable events are limited to the time of sale is on capital gains. So if you purchase a gold coin (or oil futures, or home, etc) for $1,700, and the price of gold goes up to $1,800 how much taxes are due? That's right; none. The event is a capital gain and only becomes taxable when the asset is sold. 5 years later you sell the gold coin for $2,000 and incur a $300 capital gain which is taxed based on the year you sold the coin.
Note the two can be combined. Going back to the website. Say gold was worth $1,700 at the time the site was made. You incur $1,700 taxable income. You pay your taxes, and decide not to sell the coin. You keep it for a couple years and sell it for $2,000. You incur a $300 capital gain. Why $300 and not $2,000. The $1,700 becomes your basis because it was treated at income at the time you acquired the coin. On the otherhand say gold tanks to $1,200. You would have $1,700 income when paid in gold and a $500 tax deductible capital loss on the year you sold the coin. It is possible both events could occur in the same year but they are independent events.