Stablecoins are cryptocurrencies designed to stay stable by being tied to assets like the US dollar. Popular examples include USDT, USDC, and BUSD. Traders use them to avoid volatility, lock in profits, and trade easily without cashing out to banks. However, risks exist, especially with algorithmic stablecoins like UST, which collapsed in 2022. Stablecoins are now the backbone of crypto trading pairs like BTC/USDT.