True; but do you have anything in mind that is less abstract than a graph and still expresses the continuous (or not, depending on what you're looking at...) nature of a relationship between two variables? Because I don't know of any way that is easier and more intuitive to understand than that. But maybe I'm just projecting based on my own preferences.

I think you have to understand how two things can change "with" each other before you can understand how to read a chart. Personally I think seeing something vary with time or distance is more immediately understandable than reading a chart.

Reading a chart yes, but that's because (IMO) reading is harder than making one. For example, no matter how much someone would explain, I could never understand the relationship between an angle and a sine wave, until I had a teacher made me draw a circle and an x/y axis alongside each other and project the line in the circle onto that axis. I still don't think one can really explain this without resorting to describing what happens visually. But again, maybe that's just me.