WLL, the restaurant code gives you a percentage, typically varies between 50-80% (I saw 90% once), off of the GC purchase price. So if you were buying a $25 for $10, it is 80% off the $10, net $2. So you are ahead by $23, not too bad. If you did 2 or 3 restaurants during a stay, even 1, it is a nice savings. Keep in mind though, that those are the signature restaurants, higher priced to begin with.
Those also take the Tables in Wonderland card, if you are an AP holder, and have the TiW card. That is not in addition to the above GC, it is either one or the other.
The non signatures take the AAA card for 20% off.