Each asset holds a value, often priced in U.S. dollars, which leads to another use case: trading and investing. Aside from stablecoins — which seek to stabilize the instability of cryptocurrencies by pegging an asset to something else, such as the U.S. dollar — most cryptocurrencies constantly fluctuate in price. You can trade between cryptocurrencies and national currencies (called fiat currencies) on exchanges, depending on the trading pairs available on the platform of choice.
Lustig, H. N. and S. G. Van Nieuwerburgh (2005), “Housing collateral, consumption insurance, and risk premia: An empirical perspective”, Journal of Finance 60 (3), 1167–1219.

Karony likens SafeMoon’s holder payments to the beginnings of businesses like Amazon.com Inc., where “earlier investors receive higher returns and growth because the initial risk they took was higher than those who joined later.”
Virtual currencies. Like fiat currency, virtual currencies such as Bitcoin, Litecoin, and Ether are intended as a medium of exchange that enables two parties to transact business. But there are important differences: No physical coins or bills. Virtual currencies exist only in computer code. Except for visual representation of Bitcoin and altcoins in advertising and displays, and coin-like tokens that may be produced for marketing purposes, there are no actual coins or bills. Not legal tender. Virtual currencies are not legal tender and are not issued or backed by a government. However, many virtual currencies, which are called convertible virtual currencies, can be redeemed for fiat currency on a number of exchanges. No regulation. Virtual currencies are not regulated by any government agency or authority. However, regulation is being considered, especially where virtual currencies function as securities when they’re used to raise capital and when traded on exchanges.