What is the point of the zones.rfc1918 file for Bind9?
It is generally considered a good practice to serve localhost, 0.0.127.in-addr.arpa and the RFC-1918 reverse zones on your internal DNS system to prevent sending queries from them out to the internet. It saves time (you get replies for those queries quickly), bandwidth (no requests leaving your network for zones that shouldn't exist), and relieves the load on servers upstream of you.
If you are using RFC-1918 addresses by all means serve the appropriate reverse data for the range(s) you use. You should also serve empty zones (or wildcarded zones) for the other ranges.