Yes, that is the main difference.
The SCWC includes hundreds of pages of 'coins' from Palau, Liberia, Niue, Marshall Islands, North Korea, etc that the people of those countries don't even know about.
(I believe that) the Collecting World Coins 2011 edition still extends back to 1900. Otherwise the volume would be too small! The SCWC 2011 edition is thicker than a large telephone book and only extends back to 2000. I'd bet >75% are NIFC.
If you are a collector of common circulating world coins, I'd go for the CWC. If you are a coin dealer who regularly comes across proof coins or oddities, get the SCWC.