I believe the foregoing are compelling justifications for choosing Excel Visual Basic over Visual Basic.
Spreadsheet Automation Facilitates EFFORTLESS Data Handling, Analysis & Report Generation! Sometimes people don't really care about learning(or using) all the "cool' advanced functions, formulas and techniques in the spreadsheet application they use for their work. They just want to punch in their relevant raw data _ at any time _ and immediately see the computed results generated by the spreadsheet in a manner that can facilitate their important decision making.
The savings _ from using your "in house" expertise _ in terms of money and man_hours alone, will quickly justify the investment you make in "developing the needed skills" _ especially, when you compare what you spend with the cost of purchasing a commercial software application _ or even engaging the services of an Excel VB developer.
The 80ᚼ Pareto principle is based on Pareto's theory that 80% of the results one gets in a particular endeavour will be mainly due to 20% of areas to which one has applied efforts. In business this principle has been found to be true. Your data, properly converted into appropriate performance indicators, will show you where your largest margins come from. You can then channel more time and effort in that direction.