Yes, HAAV gift cards can be used internationally wherever Visa is accepted. Just note that foreign transaction fees apply.
Use the link to the converter below to get an indication of the rate you may receive when using your Visa card to pay while travelling internationally. Change the 2% markup to 0% to get an accurate representation of the fees charged by HAAV
https://www.visa.com.au/support/consumer/travel-support/exchange-rate-calculator.html