Digital currency contracts are similar to futures contracts. It is a kind of financial derivative, and its trading object is not the real thing, but the rise and fall of commodity prices. You can make more short positions and sell them while buying. For example, if investors judge that a certain currency will rise, they can buy the rising contract, and if the price rises, they can make a profit.
It should be noted that contract transactions are generally leveraged, so the risks are relatively high. At present, the lowest leverage in digital currency is 3 times and the highest leverage is 100 times.