If you accept the default output you get slop. But you can use these tools as a starting point to get something good much faster than doing everything by hand.
I wrote a guide for this with voxel art and you can see some examples up top: https://www.tyleo.com/blog/game-ready-voxel-meshes-with-low-...
There's also an interesting set of benchmarks around giving LLMs a sort of "building-block harness and tools" to see how well they do putting together voxel-style models.
https://github.com/Ammaar-Alam/minebench
These kinds of tests which build models programmatically (SVG construction, Blender-MCP, etc) also make it significantly easier to make or request adjustments to the final output.