The importance of global illumination

Every modern graphics engine needs a global illumination solution. Rage AFAIK uses some kind of path tracing + some static lighting baked into textures(kinda like the good old lightmapping) as they have "inlimited" amount of texture memory. Unreal and other big boys, as DICE use Enlighten, CryTek have their Light Propagation Volumes.
My solution isn't  that advanced, but can be tweaked to look OK. The main drawback of it is that the lighting is static.