Can you use your Apple ID balance to buy an iTunes Gift Card to send to someone else

No, View your Apple ID balance - Apple Support states:

"You can't redeem or return App Store & iTunes Gift Cards or unused balance for cash, except as required by law. If your jurisdiction allows for refund of redeemed gift balances, you can request a refund: Contact Apple Support, then select a support category and topic. Include the following information in your request detail..."