What's the purpose of airline CREW tags? I see it sometimes on airline crew luggage, but not always. I see these come with airline name, sometimes airline base code and large CREW.

What is the purpose of these airline crew tags? After all, I got one in Crew Outfitters store as "collectible". Is this official airline tag which gives priority, different way of airport handling or something?

What would happen if I put it on my suitcase (either checked or carry-on).
It’s not an official/legal tag. Just a reminder for ground crew. At my company, luggage handlers unloading checked in luggage from the cargo will leave the bag near the aircraft (to be picked up by the crew) rather than bring it in to the terminal through the normal luggage flow. The ideea being that bag belongs to a crew member (active or positioning) and he might move arround the apron without ever going into the terminal.

Mind you this is just a courtesy, not a guaranteed thing. Should you put this on to your (checked in) bag there is a good posibility a ground operator will leave it under the plane for a while, then, when no crew comes to claim it, it will go through a lengthy process back to terminal. So your bag will have to honor of being one or two hours late to the conveyor belt.