Prototyping. Even for hobbyist builders, it's super useful to be able to 3d print something before committing it to metal, wood, etc. Outside of that, they're

Prototyping. Even for hobbyist builders, it's super useful to be able to 3d print something before committing it to metal, wood, etc. Outside of that, they're basically good for party tricks ("Everyone gets their own customized shotglass!"). If you're genetically required to jerry-rig your own whatsits rather than buy them ("$3.50 for THAT?? I could make that in an hour with a coat hanger and rare-earth magnet!!") you may also enjoy it as it provides another way to stick it to the Homo Economicus dullards.