user533: Daedalus wallet > More settings > Public key
produces an acct_XXXXXXXXXXXXXXXXXXXX string.
What can be done with this? What is it useful for?

user12: The public key is used to derive a Cardano wallet address, a wallet address is basically the hash string value that you share with other users to provide them a way to send ADA or other assets in the Cardano blockchain into your wallet. It can also be considered your bank account number. Knowing this someone will be able to send funds to you but not take the fund out of your wallet.
To take funds out of the wallet, a private key will be required. More details are given here

533: <p>Daedalus wallet &gt; More settings &gt; Public key
produces an acct_XXXXXXXXXXXXXXXXXXXX string.</p>
<p>What can be done with this? What is it useful for?</p>
 12: <p>The public key is used to derive a Cardano wallet address, a wallet address is basically the hash string value that you share with other users to provide them a way to send ADA or other assets in the Cardano blockchain into your wallet. It can also be considered your bank account number. Knowing this someone will be able to send funds to you but not take the fund out of your wallet.
To take funds out of the wallet, a private key will be required. More details are given <a href="https://developers.cardano.org/docs/integrate-cardano/creating-wallet-faucet/" rel="nofollow noreferrer">here</a></p>
