I'm chuckling at your last sentence, but overall I think your argument is really strong. The fact that pineapples require some challenge to get into, just like the Slug Club, makes a lot of sense. Of course, once you're in the Slug Club, as you point out, the rewards are sweet like getting into a pineapple.

Plus, it's great that you were able to associate him to something that he has been shown to like.

Tasha//Gryffindor