I have no problem with people viewing the $10 giftcard as $10 off the value as long as they realize they are then paying $10 for the giftcard, instead of getting it for free. Yes, your net amount spent is going to be the same.
The big thing that I see around here and a few other places, is that some people like to think, using this case, the game is for $40 instead of $50, then later they get to use their giftcard on something else to get that $10 off as well, (let’s say this “something” is $10).
If you've validated both of the purchases this way, you’ve now made the deal more than what it really is, either you paid $40 for the game and $10 for the item, or $50 for the game and got the item for free.
But I do think that the title should state the pre-giftcard value for the game, because it'll still appease the people who want to view it as $10 off, but also appease the others who think it's simply a $10 giftcard.