caching-only DNS and forwarders

[Pat Railswak]

I've set up my caching-only DNS and was left with a question.

With normal home use of caching-only DNS why should I use the
"forwarders" option in /etc/named.conf when one just gives it the 
same DNS listed in /etc/resolv.conf?  The DNS HOWTO (and others)
have said this is good, but I don't see why. The same external DNS are 
queried as soon as the local DNS doesn't find the name in its cache
with or without using forwarding it seems to me.  Is there any test 
I can do to show what's happening?  I don't like duplicating the IPs 
in two files if not helpful. Can someone explain better than the HOWTO
or my "DNS & BIND" book?