"Idiot light" vs. Oil Pressure Gauge

Yet many millions of vehicles came with them and never had issues.
Uhh, when new and under warranty....
When they were all stock and unmodified, sure. What goes wrong with an engine that is treated as a daily driver? (4 speed V8 cars not included)
If I'm rowing through the gears with a performance build or driving some distance from home, I'd sure feel better having some warning.
If you have a performance car, Having an idiot light for oil pressure or water temperature is like only having a light to tell you that you're low on gasoline.