Visualising is the first step towards understanding, which is the first step towards coming up with sound improvement ideas.
Rodrigo Yoshima is bang on when he says that visualising current workloads is a really important way of managing expectations. And that it’s very very difficult for information workers when most offices look like this:
it would be so much easier (apart from the space involved).
This is only the first level of benefit for Kanban, but it’s a huge one in its own right.