The crate often provides the opportunity for the exhibitor to leave the dog on the bench and go socialising, which I suspect is the most important usefulness of the event for some people.

So in that case, most novices, finding an interesting dog crated on its bench, will not know whom to ask to see it, or be unwilling to intrude on somebody's conversation.

And what if the crate is not on the numbered bench? The crates placed elsewhere are not numbered, so the interested observer doesn't find the dog at all!

Isn't there a KC rule about this? ( for benched shows)

The crate acts as a barrier between the Collie and his potential admirers, and will be yet one more long term influence to lessen recruitment of new owner/breeders. Other pressures are already causing this.

It repays us to display our beautiful dogs proudly for all to admire. Fundamental things always apply. I refer to the O.E.D. definition of the word SHOW.