The reason traffic lights are colored is because they are showing distinct states of the same thing and the color is the means of differentiating.

Same for transit maps: different routes are colored to distinguish them from other routes, which is especially useful if they overlap.

But that’s not what syntax highlighting does.

The equivalent of your examples would be to not highlight the syntax at all, but only use color coding to distinguish variables.

The equivalent of how syntax highlighting currently works for your examples would be if the light fixture was one color, and the light pole was another, but then all the actual lights were the same color.

I actually think highlighting only the variables with distinct colors could be extremely valuable. Would certainly help avoid mistakes with nested i/j loop counters.

Edit to add: come to think of it, it would have been even more valuable in Go, until recently anyway. The variable color coding would expose the common loop variable instance bugs, because a programmer would be instantly puzzled by the unexpected coloring.