TerraUSD is a stablecoin whose value is pegged to that of the US dollar, protecting it against the price volatility that most other cryptocurrencies experience. While the peg may vary slightly in extreme market conditions, the algorithmic mechanism of the Terra blockchain will bring back its value to the USD quickly, making any changes in UST price temporary.
As a result, the UST stablecoin is a safe digital asset to buy and use, especially as a payment method. Since its value remains stable, there is no worry of a sudden decline in UST price which can cause a loss in your portfolio.
In this manner, the TerraUSD is a safe instrument to invest in and use, especially for digital transactions.