Utility of Organizational Charts
The purposes of an org chart are specific:
Internal purpose - employees need to know where they fit, to whom do they report, who reports to them, and the corollary, to whom do they not report.
External purpose - when the "bad" thing happens, who is the person with authority.
These are all valid uses of the chart, provided that it is a maintained and current document.
An out-of-date org chart, is not only not useful, it is a detriment to your organization.