Both of this demos are not working, possibly because BuildPoints returns empty vertices: https://github.com/mattatz/unity-voxel/blob/master/Assets/Packages/Voxelizer/Demo/Scripts/GPUVoxelSkinnedMesh.cs#L109
Though https://github.com/mattatz/unity-voxel/blob/master/Assets/Packages/Voxelizer/Demo/Scripts/GPUVoxelParticleSystem.cs#L168 this version of BuildPoints returns something in fact.
Besides that, voxel size never adopts to voxel count and animation isn't working either. Pls check all demos.