New games/demos are released all the time, and often times they need an SLI profile in order for SLI to work.  The goal is to create a 1 day turnaround time from new demo release to SLI enhancement so you can be gaming in SLI as soon as possible. With recent drivers, Nvidia has been releasing SLI profiles for the newest games so the SLI Enhancemetn patch is not necessary any longer.