Graphs are the relationship layer of the visual corpus: what connects to what, and in which direction. They are not pretty pictures for a slide. They are structured descriptions an agent can walk when a prose page is too long and a schema is too flat.
Entity relationships are the noun map. Resource flow is the mine → refine → stake/spend path. System integration is how clients, chain, GRASS, and Guild Stack sit together. Gameplay-economics is where a raid, an agreement, and a guild token actually touch.
If you need the drawing rules rather than a populated graph, that is visual schemas. If you need coordinates, that is spatial.
Open graphs when you are tracing a dependency (who can raid whom, where ore goes, which service indexes what). If you want a command, that is a skill. If you want a field list, that is schemas.