Its not spiting yourself. A £25 voucher which can only be spent in one shop (and for many on match days only - hence having to queue to get in) is just not worth the incentive.
Righto.
And for those of us who would rather have the money? Or don't want to queue up in the club shop before a game? Or already have a scarf? Or a t shirt? Or can watch YouTube so don't need a DVD player? Or would welcome the cash because we would rather spend on something more worthwhile...