I needed a few shims to make something fit just right and I grabbed a piece of 3mm acrylic that was sitting on my desk, figuring I could easily cut it in the shop, but 3mm was just too thick. I could have tried to sand it down to the proper thickness, but at this point I would have had to cut three shims to the proper size, and get them all down to the correct thickness. (I didn’t want to use wood, as something would be sliding against the shim, and would wasn’t the best choice.)
I took some measurements with digital calipers, launched OpenSCAD, typed in the dimensions, and had a 3D object ready to be 3D printed in just a few minutes. While I did have to wait for the 3D printer to heat up, and print the pieces, I could easily do other work while I was waiting for the prints. I didn’t spend time cutting and sanding things to get them the exact size.
Sometimes 3D printing is the right answer, and sometimes 3D printing doesn’t have to be revolutionary or solve big problems, sometimes it can solve the (little) problem you have, quickly and easily, and that’s enough.