The problem: Is is currently impossible to create a true backup for a sheet inside Smartsheet (by copying a sheet) or outside of it (Excel backup that you offer). In both cases the cell history is completely deleted (Excel) or summarized under one name (Smartsheet Copy).
So here my user story:  
As a user, when moving or copying 
- a single row, 
- multiple rows or 
- an entire sheet, 
I would like to be able to decide if I like to carry over the the cell histories to the new location.  Currently I can make that decision for comments, attachments, but not for the cell history.  
Furthermore, the cell history should be carried over as a default (unless I de-select it) for moves that are not reversible. 
Why? 
When creating a backup, automatically, I receive only an Excel all cell history is lost. 
When I create a copy of a sheet in Smartsheet (as a backup), I also lose the  cell history (it is all changed into my name) 
Same when I copy rows. 
The default would be a safety mechanism where it is needed the most when doing irreversible actions.