Can you find the main idea please
6. Currencies have changed and developed over the course of history, but one of
the newest forms of payment doesn't even exist in the physical world. Bitcoin is an
entirely digital currency. Users of Bitcoin send payments to one another over
computer networks. These payments are nonrefundable. In other words, once the
money is sent, you can't get it back. The value of a Bitcoin has risen rapidly since
its introduction in 2009, when each Bitcoin was worth around thirty cents. At the
time of this writing, it would cost you around 7400 U.S. Dollars to get one Bitcoin.
That's quite a jump. On the downside, if the value of Bitcoin ever crashes, you
won't be able to heat your home by burning it.