The opinion to call a cryptocurrency is pegged by USD is stable as a stable coin is not correct.

Its value or stability depends on the value of USD. If USD has accident for any reason, USD-pegged stable coins will not be stable.

Furthermore, I think USD is better than stable coin, for long term. Tether USD can be collapsed, shut down but the US government and USD won't. The convenience from USDT or other USD-pegged coins is they give your fast and easy method to move your fund.

With stable coins, you have double risks: risk for value of USD, and risk for government actions.