That is very true but I would advise against it. It forces you into supporting multiple platforms. If you do everything in Perl through Win32::OLE, then your developers must know Perl and the OLE package, however if you divide your development into Perl and VBA, you put extra stress on your development by requiring knowledge of both.
That being said, I know that you're using the same objects, but the programming is done diferently, (and more robustly IHMO) in Perl. I know it sounds like a zealot's way, but I say keep it all in Perl. The manipulation you can perform on your data that you are interacting with is much more robust in Perl than in VBA.