Not everything is for sale. Things can be freely given that you wouldn't, and in some cases are not allowed to, sell.

But even beyond that some gifts that could be bought are valuable to the recipient disproportionately to what it cost for the giver to purchase them, for a variety of reasons.

> But even beyond that some gifts that could be bought are valuable to the recipient disproportionately to what it cost for the giver to purchase them, for a variety of reasons.

My point is that those are the same reasons that recipients value gift cards more than the same cash amount (though to a lesser extent).