Mass Production of "Mediocre" Trading Cards

As some popular franchises, like Star Wars and Mario Bros, become more popular, they soon release merchandise for said franchise. One of them could most possibly be trading cards. The thing is that these "trading cards" are far too useless other than being for decoration. I have no clue why they bother to release these cards if it will not clearly sell. Personally, I will stile with Pokemon and Yugioh cards at the least.