My OH got a present of these many years ago and I would certainly never buy them as a gift or if you do make sure they are in small denominations.
As we do not live in Dublin or other city there are very few places these can be redeemed locally. Our vouchers were a €100 & €50. and no change can be given. We ended up giving them to our son who was going out with a couple of friends to a posh restaurant.
I like M&S vouchers best, can be used for clothes, food, nice wine, coffee/lunch with friends