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.
You can choose to learn how to do it yourself _ or call in someone(an Excel VB Solutions Developer for instance) who knows how. Again, this would be dependent on your purpose, how proficient you are, and/or how much time you have at your disposal. Ultimately, even if someone develops a custom application for you, it should happen with YOUR guidance at every point to ensure that it does EXACTLY what you want it to do, and that you can easily _ with your developer's support/coaching _ learn how to make modifications to it in future, without needing to call back your 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.
I am keen to encourage individuals and organisations to explore using advanced MS Excel formulas and functions, in conjunction with Excel VBA programming, to develop customised spreadsheet applications that will solve typical problems end_users encounter daily in trying to record/analyse data and generate reports.