What I’ve always liked about nomograms, even more than their (1) usefulness for directly calculating as a practical tool is that they (2) make numerical relationships explicit/concrete, and (3) show an entire multivariate possibility space at once.

This has advantages for someone trying to understand a system over both symbolic equation representations, which are very abstract, and cartesian type graphs, which often are not good at plotting more than one or two variables at once.

I agree with you that with fast interactive computers it's possible to come up with other possibly better kinds of graphical representations, but the creators of those can still learn a lot from the design of nomograms.