Decentralized stablecoins are completely transparent and don’t involve custody. The collateral (if any) is in the smart contract and not in the accounts of any regulated company.
In addition, the collateral can be seen by everyone without exception, using the usual browser for the public blockchain. This increases the reliability and security of the stablecoin.
While centralized stablecoins mint or burn tokens manually as needed, in algorithmic stablecoins smart contracts are responsible for this and the process is completely automated.