Couldn't disagree more...
Imagine having the head of your accounting department who doesn't have accounting skills. Or the head of your sales department that doesn't have sales skills. Or the head of your shop floor who doesn't have manufacturing skills. Believe it or not, managers are expected to be able to step in and make sure the job gets done, and that means doing the job themselves if the normal personnel isn't available. I'd love to hear the accounting manager tell the CEO of the company "Yeah, we got audited by the IRS and they fined us a half million dollars because our cost accountant was on vacation and I didn't know how to answer their questions." You can't effectively manage a department unless you are competant enough to run the department. Period.
