Why pack+unpack?

Whenever I pull a local repository, such as

	cd /spare/repo/libata-dev
	git pull /spare/repo/linux-2.6/.git

git will pack, then unpack, the objects being pulled.  AFAICT this is 
just a complete waste of time.  Why does this occur?

Packing 1394 objects
Unpacking 1394 objects
  100% (1394/1394) done

It doesn't seem to make any sense to perform work, then immediately undo 
that work, just for a local pull.

	Jeff