True, but incomplete. If you know something, you can use that as leverage in a situation where that knowledge is useful. If you know a lot about a subject, and make that known to others, you attain the status of 'expert', which is a powerful position.
What's missing, of course, is the fact that knowledge isn't the only source power, nor is it even the greatest. Knowledge is more of a starting point, I think, than an end. For example, knowledge is pretty worthless unless you know how to evaluate the truth of that knowledge and how to use that knowledge.