The Client Safe report is useful if you need a report that you can share with your client, and want to use terminology that's more appropriate for their purposes. For example, in the Client Safe report, what Display & Video 360 refers to as "Revenue" is instead called "Cost" (since this amount is the cost charged to the end client).
Can I send this report to my client?
Client Safe report is useful for tailoring terminology to clients, but it does disclose instances of Media fee and CPM fee. So depending on your configuration, these fields may include information (like Display & Video 360 fee or margin) than you don't want to provide.