Excel user defined functions are incredibly powerful and sometimes you want to make functions that can do different things based on inputs and it can be very helpful to have optional parameters.
Optional parameters allow users to omit arguments when using functions in Excel if they are unnecessary. A very common use-case is when a true-false (boolean) is being used. Why should the user have to type in False when they can just leave it blank?
In this video we very quickly demonstrate the use of the Optional param declaration.
