I have had to debug insane Excel sheets, which were used to generate C code, based on the geometric properties of an object.

Excel works very well for describing many, simple relationships. It totally falls apart the moment you have complex relationships, as they become mentally untraceable. Functions allow you to abstract away functionality, referencing cells does not.

I am pretty certain that Excel is one of the most misused tools and suffers the most from "I use it because I know it".