The benefits are obvious.

WCS is the most famous Warcraft mod for CS:S. There are 503 servers currently running WCS (25/04/2009) with total capacity of 9000 players which is a huge number.
Everyone who is publishing races wants those races to become popular.
So, how to make this possible? Yes - we are here to help you.
More than a half of WCS servers do run custom races which are taken from this forum.
Advantages:

• The "Approved custom Races/Shop Items/add-ons" is the first where server admins are looking at.
• Approved code means that customer has sort of insurance that code is robust and accurate.
• Approved code is a proof for customers that code is actually custom rather than stolen
• Approved code has a great chance of being included in Custom Packs and some even to next official WCS releases
• Profit and only!

When your code is approved it is moved to Approved board where you are still able to post/discuss/modify previous posts/modify code.