I love that having a 3d printer means you can create custom parts when you need them. I wanted a set of leveling brackets for a router table insert. Sketched up something in Solid Edge, sent it to the printer and a few hours later I have what I need. Nothing complex but functional. Used PETG on this set.
I’ve fixed things like a shaft bearing for a grain auger, a new impeller for a water pump, all sorts of project boxes, mounts and handles. My 93 yo uncle will sit there and watch it for the entire print, just shaking his head. And then when the neighbors come by for coffee, he has to show them the new part and the broken part. I think he’s prouder of the machine than I am.
My great-uncle never learned how to use a computer (well, other than the TRS-80 he got before he retired). He was pretty mechanical though. Even if he probably wouldn’t understand much about how it worked, he probably would’ve appreciated 3D printing if used for a car part or something!