I'm really beginning to hate this phrase.
Why? Well, firstly it long ago achieved the status of cliche - used unironically only by the intellectually lazy.
Secondly, and much more importantly, it emphasises an instrumental view of knowledge (i.e. if I know this then I can do that which will give me more money, beautiful women, etc.). But really the most important thing about knowledge is it allows you to achieve the greatest pleasure (but no, I don't mean carnal knowledge :-).
For instance, I just learnt that the reason the pre-moderns avoided mathematics is that it was focused on arithmetic. But multiplication using Roman numerals was extremely difficult so in many cases, figures were eschewed in favour of phrases such as 'a little bit' or 'a large proportion'.
Now, this knowledge is of no immediate practical importance or use to me - so no power is involved. But the fantastic frisson of pleasure I just got from learning, understanding and fitting this into all the other things I know is one of the highest goods I know.