What is the purpose of dyeing traps? I know, sacrilegious. Waxing keeps them from rusting, speeds them up and covering them camos them. Why dye?

Hopefully someone will come along and give you the scientific answer but it’s just another tool to keep your traps working there best and lasting longer.Same for wax and doing both is twice as good.My 2cents

I dye all my water traps so they blend in without being covered. A bright shiny mink trap under an inch of water just doesn't do it for me

This. Dyed water traps blend in with the bottom.

And dyed traps blend in when they don't stay covered like they are suppose to.

Harder for thieves to see too.

I dye traps to temporarily neutralize rust. No other reason. Blood red rust has an odor, and is hard on your springs. I don’t wax traps because I spend more days sweating and wearing a sombrero than a jacket and wax in 95-100 degrees no bueno

Dying traps is a misnomer Killbuck, it’s all about tannic acid which when it chemically reacts with iron oxide (rust) it converts it into a stable, dark-colored (black) compound called iron tannate, it turns everything black, such as a dye would, hence, dying traps! The problem, IMHO is that trappers read this BS about “dying” traps and they are referring to color change but nobody seems to want to investigate the “WHY” of this treatment of trap rust and the cause of a black color. Tannic acid is a natural distillate from many kinds of wood such as black walnut nuts & hulls, hickory, logwood, etc., and many, many others similar. The thing is most of the logwood powder advertised by trapping suppliers isn’t real logwood, many are just plain old dye to change the color of your traps but there are a few who do supposedly sell the real deal but you’ll have to ask.

The "dye" stops the rust already formed. Read Seldom's post above about the dye not really being a dye. It is a good explanation.
Dyeing them won't stop them from rusting in the future, but it will kill all the rust present. And in my experience dyed traps don't rust as fast and as badly as untreated traps. But they will rust unless you coat them with wax or something similar.

As turtledale says, dyed water traps so the blend in uncovered. You can wax, paint, powder coat, or whatever traps wWhether they are land or water to prevent further rust, but if you don't kill the rust first, they will continue to rust underneath the coating.

As many others have said it serves two purposes of neutralizing rust and blend the trap in with its surrounding area. I have some old Victor #4 longsprings that nobody treated since maybe they were new and the bottom plate is covered in pitting from rust. You start buying some high priced beaver traps or coyote traps it is cheap insurance to protect them and keep them in good condition for as long as possible.

Just keeps the steel healthy, and helps us all sleep at night. (Ignore the time I’m posting this at, I’m sitting in an airport waiting and it’s entirely too loud for sleep)

That ain't night, it is morning when you are posting. You should be up already, even if you're a faller that gets to sleep in.

My saws won’t start till 6am, I’ve tried, it’s them that sleeps in lol