Why do people not connect all their cycles nodes? So I downloaded this blend file to figure out how to bake out textures. In the process I see that he has some very complex node set-ups all to end up seeing them not connected at the end. Why have such complex node systems just to not connect them?

This is not the first time I've seen this. Please someone explain this logic to me.
the disconnected nodes are the original materials (textured, with normal maps, diffuse and glossy shader), the connected nodes are the baked materials (baked texture plugged to emission shader)