Adobe Illustrator has always been a bit elusive to me. Despite that, you'll notice it plays a significant role in my workflow.
The reason is simple: it's an exceptional vector editing software. While I primarily create assets using 3D or Photoshop, Illustrator comes into play for generating patterns and symbols, as well as editing existing vector images.
Moreover, Adobe Illustrator is instrumental in translating 2D concepts into 3D models using splines.