As above, what the "brains" is really for is not so much to assist in catching but more to make the dog "handy" and easier/faster to train and handle. As an example if you want a dog to work out of sight on the other side of a hedge you're ferreting a handy dog can be trusted to do this and will bring any rabbits either to you or to it,s spot at the hedge back.
I won't say no other type of lurcher can be made manageable like this but IMO it's easier with a collie cross.