With cryptocurrencies still in the news, tumbling 10 percent to 20 percent in recent days thanks in part to a change in calculating how the coins are valued, the debate rages on as to whether bitcoin, ethereum, ripple, bitcoin cash and litecoin are, in fact, money.

The Oracle of Omaha, Warren Buffett, said on CNBC Wednesday morning that the speculation in bitcoin, and other cryptocurrencies, "will have a bad ending."

Appropriately, dogecoin, a digital currency that began as a joke based on an internet meme, has risen sharply in recent days and hit a total value of $2 billion. By Wednesday it had retreated to a market value of about $1.5 billion, according to CoinMarketCap.

But rather than seeing all these digital currencies as a small part of a larger system known as blockchain, I am predisposed to view them as just speculative tokens in a cryptocurrency bubble that has inflated more quickly than any other in financial market history.

Admittedly I'm green with envy for failing to foresee the explosive rally in the price of bitcoin when it was first brought to my attention several years ago.

Having said that, there are many things I find quite ironic about how bitcoin and other "cryptos" are described.

First, they are largely denominated, or discussed, in U.S. dollar terms.

If, however, you are buying and selling these currencies on the various exchanges, then, generally speaking, the currencies trade against one another.

Bitcoin, bitcoin cash, ethereum or litecoin, are cross-traded, just like on traditional foreign exchange markets, where dollars are priced in value against yen, euros, Swiss francs or Chinese yuan.

These exchanges are easy to pull up on a computer screen but not that easy to use. It's much easier to buy and sell dollars, stocks or commodities than it is to trade bitcoin and its brethren.

The conversion of one crypto to another is relatively easy on these embryonic exchanges. But getting your digital wealth converted into cold hard cash is more problematic.

If the dollar is archaic, as the crypto-enthusiasts believe, why not speak only in crypto-terms?

Because the dollar remains the reserve currency of the globe. Its usage remains widespread, accounts for roughly 65 percent of all global economic transactions.

In the U.S. alone, one of the broad gauges of the nation's money supply, known as M2, totaled nearly $14 trillion as of December 2017. And that doesn't count even broader measures of the U.S. money supply and the dollar-denominated accounts held all around the world.

Nor does it count the tens of trillions of other sovereign currencies sloshing around the globe, all readily convertible to one another.

The total market value of all cryptocurrencies is roughly $600 billion, give or take a hundred billion. And while the growth has been impressive, it remains very difficult to walk into any establishment and exchange a digital token for goods or services.