No, you misunderstood my point. I didn't mean "use macros that are invoked by Perl using Win32::OLE". I meant "Use the macro recorder and VBA instead of using Perl". VBA and the macro recorder (which ultimately is a shiny wrapper on the underlying VBA) are the tools explicitly designed by Microsoft for automating Excel. It's just that with the power of Perl, you can do many other things that are difficult or impossible when using VBA.
After Davies explained, I now see how reusing a single instance of Excel could lead to data loss. Perhaps the authors of Win32::OLE should be contacted so that the module examples have caveats about what it really means for the system when you reuse a running Excel instance.