I noticed that on Etsy, when you mouse over products after conducting a search, two buttons display in the upper right hand corner to either "heart" the product or add the product to a list. How effective would that kind of interaction be with an add to cart button?
For a retail site, I would consider "Add To Cart" to be a piece of core functionality. Implementation of core functionality should not magically appear and disappear. While it seems relatively clear in your description, I think this can be confusing to users. If they have not hovered over an item yet, there will not have been an "Add to Cart" button/link available to them at all.