WHAT IS ILLUSTRATION AND WHY USE IT?
Illustration: A picture or diagram that helps make something clear or attractive
In my case I have used illustrations many times to help for example show a process, demo a new product (before it's even in production), create conceptual visuals that sometimes conventional photography just cant do or it's logistically a nightmare or too expensive to produce, show clients what their home, staircase, or exhibition stand will look like before a cent is spent on production. I have also created 3D visuals of a clients entire product range which means its easy to create 'photos' of them from any angle, in any group, showing any feature at any time.
It is a cost effective process, especially if you plan on re-using the 3D models for different applications and if the products change, generally its quite simple to update the 3D model and continue the process.