The ability to lock individual tabs so that unauthorized users can not open them to either view or change content.
Locked tabs could still be seen from in the "hide/unhide" drop down but unauthorized users would not be able to open the tab.
Teala Coleman commented
It would be ideal if you could share an excel document with a group but have one or more tabs password protected. For Example: Say you're sharing a document called Donuts with tabs called Sprinkles, Frosting, Decorations, and secret recipe. I would like to share the document with 8 people but only allow 2 of those people to view/edit the"Secret Recipe" tab. I would prefer if the tab was displayed at the bottom of the document by all 8 but would not display the contents of the tab without first entering a password.
Alternatively in vba do a thisworkbook.sheets("SheetName").vislble = xlveryhidden
Kenneth Barber commented
Hide your sheet. Go to the Review tab and Protect Workbook. An unauthorized user will not only not be able to view or change the content of the sheet, but they will also not have access to the list of hidden sheets unless they press Alt + F11.