Mesh Paint allows one to paint multiple textures over a surface in very distinct and unique manners. For instance, my goal was to be able to paint dust in cracked areas of a wall. That will provide a more believable look and you can stylize anyway you want.
Advanced Mesh Painting in UDK from 3DMotive sets quite an intensive learning curve as there is MUCH to understand about the process. It involves setting up your materials in quite a unique way.
Here are some pictures showing the logical, but craazy node system I've ended up creating and re-creating several times:
With the help of this new tools at my disposal, I have more control over how colors and texture patterns behave/appear on my game levels. Once you practice and research the technical elements enough, it all becomes art again and the tool is just second nature.
Here is a test scene, showing exactly what I am able to achieve with Mesh Paint:
UDK is starting to make more sense now, becoming more familiar and understandable as I peek into the inner workings of various tools. There is still and always be a lot more to learn, but as your capabilities grow, you feel more confident.