Say I'm a DIY enthusiast that uses a printer as yet another tool to do the job whenever it can do the job better than other of my tools. So far I do the designs with OpenSCAD and qcad, and print them with a Tronxy P802 (aka budget clone of Anet A8).
If I consider that a particular thing could be useful for others, then I publish it, hoping that others will do the same and I won't have to always redesign the wheel anew. Previously I published the design on the slowly breaking apart thingiverse (thingiverse.com/jprofesorek).