Author of VTracer here. Finally being able to comment on hackernews before the thread got locked.
Would be interested in learning about your workflow. Is it a logo generation app?
I feel like this is an example of "Machine learning is eating software". Raster to vector conversion is a perfect problem, because we can generate dataset of infinite sizes and can easily validate them with vectorize-rasterize roundtrips.
I did have an idea of performing tracing iteratively. Basically by adjusting the output SVG bit-by-bit until it matches the original image within a certain margin of error. And optimizing the output size of the SVG by simplifying curves if it does not degrade the quality. But VTracer in its current state is oneshot and probably uses 1/100 of the computational resources.
VTracer seems to perform badly on all the examples. I suspect it can be drastically improved simply by upscaling the image (via traditional interpolation, or machine learning based) and picking different parameters. But I am glad that it was cited!