In short
Major dollar stablecoins like USDC are fully reserved and designed to stay at $1, making them safe for everyday payments. Risks to understand are issuer/reserve risk and rare de-pegging events; using reputable stablecoins and settling promptly reduces exposure.
Understanding the risks
A stablecoin is only as sound as its reserves and issuer. Reputable coins publish attestations and hold liquid reserves. The main risks are a temporary de-peg or issuer trouble; accepting well-established stablecoins and not holding large balances longer than needed keeps risk low.
Part of our guide to stablecoins for business.