Voronoi is a mathematical pattern. It's that simple. It's popular in 3d printing because it's a pattern which can be used to create holes in objects using a very organic and aesthetic way, and saves a lot of material costs while creating something interesting to look at. Voronoi patterns can be created in almost any 3d modeling application these days. I've seen it created in Zbrush, Rhino, 3dsmax and others (all of which use different types of design elements).