If the code was stored in source control with a separation between dev and production the intern might be able to raise such a Pull Request but it would never get approved without oversight from someone more senior. This Code Review process is almost completely impossible in Excel.
... and then you have two problems. I have never seen an environment converted to SharePoint that didn't suffer badly from the conversion.
And the Excel vs <other language> source control issue isn't history, it's "go ahead and try to diff between two versions of an Excel sheet" vs "diff two versions of that source file".
Unless I've never heard of the tool that can digest two Excel sheets and tell you what formulas differ, or cells. Please correct me, anyone who knows of one.
