If you are designing a new building or home an illustration of what you are going to get is very important. An artist impression based on a 3D computer model gives you an acurate depiction, and when you add the textures and materials you can reduce any suprises.
It also adds to the excitment when you can see your house come to life.
If you are marketing your homes then an illustration becomes even more important. A basic CAD drawing is good but an artist impression brings it to life.
The model can be animated with a fly around or fly through. It’s amazing how much more real it becomes when you can see it move.