Since this thread is about WD40, I believe that different riders have different sound thresholds for what constitutes quiet operation.

WD40 leaves a chain rattly-sounding after one ride. There may be no squeeking (and won't be if it's a decent, modern chain), but the rattly noise of the rollers is very annoying to this rider.
And any excess WD40 of course flies off if not well-removed with a cloth, staining the rear tire (though not noticeably affecting braking performance).

The same is true of any other dry lube that can't damp the free rattling of the rollers, but for sure some cyclists just don't hear this at all.
This somewhat puzzles me because at my age and having played with explosives, arms and having raced motorcycles for years, I still need to have some real "oilyness" in my chain. I lube with a roughly 20% oil in solvent mix (the solvent being hexane with ptfe particulate that I expel into a Triflow or WL squeeze bottle).

I recall that WD40 contains a very low percentage of actual oil (after the kero/solvents evaporate), just too low to make a chain very quiet for long imo.

I also go by the axiom "you can't wipe too much lube off of a chain" using a typically well-used terrycloth shop rag. And I never "clean" my chain, except perhaps after riding in mud (while hosing off the whole bike).