Yeah, marketing is so deceptive, just to get people to buy things.
Optimus and Bumblebee aren't in much of Rescue Bots either, but they have more toys than the cast characters, and featured on DVD covers... because regular people (parents buying them for kids or as gifts) recognise the iconic character of Optimus and might remember that it was the character that the intended recipient liked (if more kids are fans of Bee and Op than other characters, they get plastered on all the kids merchandise, including DVDs - I think there was a Rescue Bots DVD that had Optimus or Bee on the cover, but didn't appear in any episodes on the disc).