To me, the Tasks add-on seems pretty close to a working “gift card” solution. If a service could also be set to not have any staff member associated to it, and a auto generated unique coupon code for each sale – Bingo – a gift card. This could be redeemed as a normal coupon code when booking a service later.
Please see this image for what I have in mind: https://www.dropbox.com/s/0by7dw5nfnhy0by/giftcard.JPG?dl=0
PS! There are currently two other gift card requests for Bookly: