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.
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.
Deciding What Spreadsheet Application To Use. This would ultimately be up to you. The big "fight" has always been between Lotus 1θι and Microsoft Excel. I started out with Lotus 1θι back in 1993 and learnt Lotus Macros programming(via self_tutoring). I eventually used this skill to develop _ in my free time _ various custom spreadsheet solutions(that were formally adopted for use in the departments I worked in as a brewer/manager in Guinness), before switching to Microsoft Excel in 2001. Subsequently, I developed my Excel Visual Basic spreadsheet programming skills (also via self_tutoring), because the company had chosen to adopt MS Office during the roll over to year 2000.
In addition, visualise it having dynamic query/report drop menu interfaces, and a variety of custom buttons: for navigation(within and between worksheets), printing, data export (as PDF documents or spreadsheet files), saving, auto_data filtering, auto_charts plotting, auto_backup of files, user login authentication (for documents with sensitive or confidential content) etc.