Pizza Guy, Excel is not a secure platform. Even with code and a password, it would take less than 5 minutes to find a ******* on the web to display the sensitive information.
I'm agreeing with you that no sensitive information should be put on an Excel worksheet.
I'm disagreeing that trusting passwords and protection is sufficient.
My personal approach is that protecting the data from clumsy users is a valid use of time.
But trying to achieve security inside Excel is futile and a waste of a developer's time.
If security is important, don't use Excel.
IMO. There are others who disagree.