I was looking through old pics and found one of this test film I have.
It might be hard to tell from this, but what it is is progressively higher line counts of halftones. You burn this on your screen, and it shows what line count prints best.
What those darker outlines in steps are is suggested mesh counts for the various halftone LPI counts, but also showing the reduced contrast range
What happens when you expose this film on mesh and then print it, you immediately see the drop out at the bottom end of 5% lights, and the filling in at the top end of 95% darks.
It shows you pretty clearly what you can hold on your exposing and printing system, and Dr Moire appears where there is a math mismatch with line count and mesh count.
None of this really matters if you are just banging out some raw coarse halftones, especially just black. But if you are trying to print some serious 4/c process, you need to be able to print the widest possible contrast range, and not lose it during the run, because this will cause weird color shifts when the other colors go down.
Like Richie said, one of the key issues is how high a line count you have/need, which is determined by viewing distance - its better to print coarser and keep your range and all the dots, than to force it and lose them.