Where it runs out
The examples above are the cases the design is good at. These are the ones it is not, and they are all consequences of the same two decisions that make the rest fast: a mesh becomes a fixed-resolution image, and everything else becomes vector nodes that are written out one per drawn thing.
None of these is a bug, and none has a workaround hiding in a keyword argument. They are the shape of the trade, measured: where a curve stops flattening, where extra data stops reaching the screen, and where the file grows faster than anything downstream can consume. The general limitations of the library – fonts, density estimates, projections – are documented separately in Limitations.
A mesh is an image, so cells past the pixel count are wasted
What an animated slider costs: size and save time against frame count