This is really interesting, thanks so much for the reply! It's awesome to get a little bit more insight into projects like this, especially because I've got a limited (but growing) insight into both playing games and building projects with game engines.

Just to parrot back what (it sounds like) you're saying: using voxel-based assets in a game with community-contributed assets that extends itself using procedural generation is that the difficult of integration tends to be lower. This is because voxel shapes allow "artists" (which don't necessarily have to be highly-skilled) to build game-appropriate assets fairly easily, and for the generative process to more easily combine those elements into a cohesive world model than might be possible with polygon-based assets. Does that sound about right?