I think the reasoning could be that most people who like cosplay have at least some interest in Japan.. which sounds like something I would expect to be true.
Yes. However the business objective isn't finding people with interest in Japan. The objective is to reach people who would likely be interested in buying exotic candy. The further removed from your objective the marketing vehicle is, the exponentially higher the likelihood that the marketing campaign will fail. While I suppose Bemmu hasn't really been a marketer before, I see even "professionals" making errors like this all the times in search of chimera like "engagement" rather than linking marketing strategy and execution directly to the business objective.
buying exotic candy...from Japan. Having known a few people who are into manga, not even cosplay, they often find oddball Japanese candy interesting. Maybe not enough to buy because of an unboxing video, though.
