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.
2. Sourcing Capital _ For Expansion or Startup. You can make it easier for banks and prospective investors to back you financially and/or take the decision to buy into your business. Those already running their businesses will know that banks like to see detailed business records that show in real terms all aspects of a business' performance. Without detailed and comprehensive spreadsheet tracking, it might be difficult to show this. Agreed there are software applications that capture most of these. However, sometimes, you want to highlight certain scenarios or trends in a way that an off_the_shelf application cannot accommodate due to the uniqueness of your need. It is in this regard that the use of spreadsheet tracking becomes relevant.
One Possible Application: Plotting a pie chart based on income contributions from all your products and services(daily, weekly or monthly), and reviewing the automatically computed percentages/visual pie slices, can give very illuminating insight.
Variable Costs Control/Reduction was a strategy that worked extremely well for the company. Most memorable for me as a brewer, was the manner in which huge monetary savings/profit gains were made by successfully implementing variable cost reduction initiatives. For instance, a brewing ingredient switch was made to a more readily available local alternative which was many times cheaper, resulting in phenomenal savings and progressively increasing profit earnings even though the price of beer produced was not raised. This practice was routinely applied across the brewing and packaging processes in line with a well thought out plan.