There's no reason they can't instead be used to show how data transforms. The sort of 'flow wall' someone sees in a large industrial setting (think water/waste water treatment plants, power plants, chemical plants, etc) or process mockup diagrams for spreadsheet heavy modpacks (I'm looking at you GregTech New Horizons).

Data can instead be modeled as inputs which transform as they flow through a system, and possibly modify the system.