I believe the foregoing are compelling justifications for choosing Excel Visual Basic over Visual Basic.
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.
For the purpose of creating custom financial and business management solutions that solve your identified problems, and give you control/ownership, without burning a hole in your pocket, Excel VB offers an amazing variety of possibilities, in the hands of an adequately skilled user.
So, (when considering the automation I speak about) do not think about spreadsheet documents containing one or two click_able buttons that allow a user print a page or copy some cells from one sheet to another. Instead, I want you to picture an application(or Entreprise Information System) that customises the appearance of your spreadsheet workspace(to take advantage of maximum screen capital available on your PC), and offers you custom "floating" data entry forms.