Mostly because the cardback on the other side is generic as well.
The complication is a language requirement we have here for merchandise to be labeled in both official languages of Canada, English and French. To get around that Hasbro manufactures the tri-logo or tri-language cards with English, French and Spanish to sell in Canada and Mexico. The cardback is generic by wave and the back of the card will not have figure specific information on it, rather a picture of other "available" figures. That way they only need to print a single cardback for each wave (or in the case of OTC, a single cardback) which is considerably cheaper.