Actually, it's because of a conversation I had the last time I posted to the network. When I was asking about the cave, someone mentioned that they had some trouble with the Pokemon in it while they were making their way through, on account of there being just so many of them. I was trying to figure out how much this item would have helped them.

I think the answer to that question is obvious at this point. Take note, Hikari, carry repels if you're going into caves.