Casio CZ/ VZ/ FZ - Pro Series

>  Actually is it simple and straightforward. Simply connect a
> 9 volt battery strap to the + and - battery terminals. Connect 
> a square battery holder for 4 AA. 

I need to do this mod asap -- great! 

But I'm confused by the above directions.

What is the point of using a 9v battery strap? Is there one? Isn't
that just a couple of wires with 9v connectors at the end? Why not
just wire the battery holder straight to the + and - terminals?

eh?