Because sometimes you need a little visual stimulation
I've had this image on my desktop for some time now, and can't remember exactly where it came from. But I know I like to look at visuals like this when I'm feeling a little 'linear' in my thinking. When you've been poring over a lot of text and spreadsheets, mindmaps can be a good way to get your brain thinking in different directions, and suddenly you feel a lot smarter than you were 15 minutes ago.
This particular mindmap is titled 'Behavior Change Program', and that's really what change management is all about: Helping the organization, and the people within it, to change their behaviors, both on a corporate level and an individual level.
The next time you're feeling stuck in the process of change, try a mindmap - you never know where it could take you.