Yellow in retail usually signifies something as being cheap/reduced in price. Yellow is the colour used in different supermarkets for the labels showing the new reduced price when it needs clearing or near it's use by date.
It's bargain imagery and possible impulse purchase product.
True but it's a cheap trick considering how the old Platinum games were coloured in silver. We're not just talking about a yellow price tag but an artwork which have been ruined for the sake of it.