the Etsy gift certificate requires direct checkout, which means it can only be used by US Etsy sellers and buyers, and has to be purchased through Etsy, and can be used on any shop on Etsy that accepts them.
You can, however, create your own gift cards exclusive to your own shop now that Etsy has implemented the "fixed discount" feature, but they don't work the same way. To use this sort of gift card, you need to create unique codes yourself, and they can only be used on purchases of equal or greater value than the code, I believe. It's all in the same coupon codes section.
