The 80ᚼ Pareto principle is based on Pareto's theory that 80% of the results one gets in a particular endeavour will be mainly due to 20% of areas to which one has applied efforts. In business this principle has been found to be true. Your data, properly converted into appropriate performance indicators, will show you where your largest margins come from. You can then channel more time and effort in that direction.
Another question I ask, in answering the "Why Excel VB?" question is : "Why re_invent the wheel? ". My experiences(and those of others who favour the use of Excel VB like I do), confirm that to organise, and analyse data for (financial/management) report generation and decision making, you will save hundreds of hours using already in_built, pre_programmed Excel functions compared to a situation where you used Visual Basic proper. All the functions needed to achieve the above purposes already exist in Excel, so that you don't have to write them all from scratch as would be the case if you were to use Visual Basic. 3.It works even when you lack "In House" expertise.
In addition, an Excel VB developer( who in many cases will tend to be a user turned developer, and is therefore likely to easily see things from your perspective) _ unlike a programmer _ is more likely to be positively disposed to working with you to ensure the application meets your practical needs. S/he will readily understand that the final application is meant to help solve a real problem(s), and will therefore build it to match those expectations.
From this point on, I will refer to only one of the above mentioned applications, because it is my preferred work environment. That is Microsoft Excel. I believe users of other spreadsheet applications will be able to adapt whatever I say from here for use in their own peculiar environments.