Functional analysis vs complex analysis

Why do companies use functional analysis?
The functional analysis is important as it provides an overview of value creation within the supply chain in general and the related party transaction in particular.
It provides an understanding of the relative contributions of the parties to the transaction and their roles in overall value creation..
Why do we need functional analysis?
Functional analysis allows product managers to break-free from thinking about problems and solutions the same way as they always do.
Product managers tend to get too close to the product, which prevents us from seeing problems and solutions from different lenses..
Functional analysis is conceptually more difficult (starts off with point set topology) and has both real and complex analysis as prerequisites._{Dec 7, 2014}

Why do companies use functional analysis?