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.
At times, they would prefer to click a button that says "Print ABC", or "Print XYZ" report, instead of having to crawl all over the huge spreadsheet(and get "lost" every now and then), to highlight and print different report pages. Using a custom built data entry form to make data entries into 14 different cells in different parts of a table(at the same time/with one click) would, for them, be "heaven" compared to making the entries one at a time.
In effect what I am saying is that companies which get the most value from spreadsheet automation(including using it to avoid expenditure on less adaptable commercial off the shelf applications) will be those which empower their users to routinely generate "in house" solutions. In such companies, you will find that only when the requirement becomes considerably specialised or complex, does the IT department get called upon to develop or purchase software solutions for user departments or functions with significant data recording and analysis needs.
This last point in my opinion is ONE major benefit you must seek to extract, if you choose to engage the services of a developer. S/he should be able to help you develop (in_house) expertise needed to maintain the application AFTER s/he is gone. If you fail to ensure this, all your cost_savings from using the application might end up being spent paying the developer to maintain the application over time in the future!