Utterly stupid little things, its money that is less useful in EVERY situation and expires! Even at the store where you can use it, what do you do with the money that's leftover but too little to spend? Especially at expensive places, you could very well end up with 10-20$ OF YOUR OWN MONEY, that you can't even use!
I was given a dunkin giftcard for volunteering at a repair cafe. First of all I'm on a diet but secondly I stuffed it in my wallet so quickly I completely forgot about it. The day I remember and go through the trouble of attending such a wretched establishment I was told it expired after I finished giving my order! After such bother to try to use this cursed thing I refuse to return fruitless from my endeavors so I paid with my own cash.
It is now, sulking into my hashbrowns and Boston cream do I realize I am now poorer, fatter and fucking miserable. FUCK gift cards.
To show they know you, at least a bit. Cash can obviously used by everyone about anywhere, but for that reason it can be given to someone you don't know at all and they'll like it.
A gift card shows that the giver at least believes they know the gifted well enough to know where they like to spend money. They just don't know them well enough to know they would like "this specific thing" and know they don't already one one.
I got a gift card to a steak restaurant as a thank you for a huge favour. It was the last place I'd go for a meal. I'd rather have had a book token - I could have bought half a dozen books, and instead it was a not very enjoyable meal for two.