This is nice to be able to just download this rather than having to manually track down each of the files for the various heads available. Saves a lot of time and trouble IMO. It really is annoying that we have to do this though. NWN should be smart enough to know that if a module uses a hak, then any heads in that hak should be available...
PS. This is really convenient and a time saver and all, but I do suggest removing them when you aren't using them (eg after creation -- once the character is created, the CEP2 hak takes over assuming the module actually uses it and if it does not then no one sees the correct head for your character but you anyway.) Apparently any sort of overrides can be bad for a server for some reason. I'm not really sure why since these are on the client side, but it apparently is true from what I've seen.