The idea of the partitions is that when a puppy is being potty-trained, you should have the crate as small as possible, allowing only for the dog to sit up, lie down, and turn around, so they don't have room to potty in one spot and then sit somewhere else, because that will prolong potty-training.It gives the puppy more space when its little,
I haven't had a young puppy in almost 16 years (I prefer to adopt adolescent or adult dogs) and I didn't crate-train that dog or any previous dogs, so I haven't tried it personally, but that's what I've always heard.