Determining whether to use Microsoft Word vs. Microsoft Excel is debatable. Typically, I look at the usage goal of the end product. Most end products can be created in Excel, Word and/or PowerPoint.
If the end product will be maintained online and will require formulas (i.e. automatic mathematical expressions: add, subtract, divide, etc...), I prefer Excel. If the end product will be printed and maintained manually (with no need for automated calculations), I choose Word or PowerPoint.
For Example, if an Agenda needs to be maintained in a format that includes the tallying of the amount of time to be spent on each topic, Excel could be used to contain a formula to calculate the total hours spent.
Another example is Invoices. If the desired end result is to create a document that is printed and used to hand-tally totals, tax and discounts, a Word document would be desirable. However, if the desired end result is to create a document that will be used on-line to maintain totals, tax and discounts, an Excel document would include formulas for the calculations.
We can discuss the options and benefits. Ultimately, the choice for the best tool that works for your end product is totally up to you.