Schematics (of any sort), block diagrams, general spatial awareness (including anything related to puzzle pieces/packing, like circuit layout), most physics problems involving force diagrams, anything mechanical, etc. The text representation of any of these is ludicrously more complex than simple images.

If you sit someone down, that works in one of these fields, you'll quickly see the limitations. It'll try to represent the concepts as text, with ascii art or some "attempt" at an ascii file format that can be used to draw, and its "reasoning" about these things is much more limited.

I think most people interacting with GPT are in a text-only (and especially programming) bubble.