An area where 3D printing shines is when you need a custom part that has to perfectly interact with another part. In this case I had a soundbar with a unique shape and needed to design brackets to mount it on the wall.
I used Fusion 360 to design my brackets and approached it in a way that guaranteed a perfect fit. A simple but powerful workflow is to use the Attached Canvas tool located under the Insert menu to bring in a picture into Fusion 360. Once the picture is calibrated you can then create a sketch by referencing the image to guarantee a perfect fit. Using this method along with a pair of calipers can be a life savor especially when you don't have technical drawings to rely on.
After 3D printing the brackets you get to experience the sweet satisfaction of a perfect fit on your first try which doesn't happen often with 3D printing.
*In hindsight I should have designed this in the XY plane instead of the XZ plane. Not a big deal but would have saved a step from having to rotate the model in a slicer program for optimal print orientation.