Oh sure, it's not like Bride Cactace's artwork is displayed on the advertisement or anything as the main draw for this step-up gatcha. And it's not like Cactace herself was already in a previous rainbow ticket deal awhile back (she as, in case you can't detect sarcasm).
Face it, the Bride Cactace is as much of a "Bonus" as the meat in a Meat Bun.
Just eat the Bun. The meat is a bonus. Totally. We're just selling you the bun. The meat is a bonus topping, just pay twice the amount you'd usually pay for a meat bun.
Don't be fooled by Nutaku. This Step-Up had every intention of making Bride Cactace the main goddamn draw of the deal. Don't just eat up any "buzzword" Nutaku throws at you. Whether or not Bride Cactace is a "bonus" or not, this is a bad deal enough simply because it alienates a certain subset of customers who would otherwise want Bride Cactace, but are "unfortunate" enough to already own original Cactace. Don't they want more money?
Like I said, wait until the Orchid Bride Step-Up when they introduced 6* Bride Orchid as a $60 bonus only after spending $50 on buying the normal 5* Orchid. I'd like to see you justify Nutaku's actions then.