Among the many coins that exist today, only some of them are stablecoins, meaning they are tied to a specific fiat currency. For example, USDT, USDC, BUSD, DAI, etc. Their price is calculated based on the rate of the regular fiat US dollar. That's why they are called stablecoins, "stable" meaning steady. Stablecoins are actively used in trading when it is necessary to lock in profits. The rest of the cryptocurrencies are quite volatile coins, meaning their rates often change rapidly. If you invest your money in such coins to make a profit, you need to always stay on top of the situation, be online, and monitor the prices. This helps you quickly decide whether to exchange, sell, or buy a particular coin.