I always drop mine when the crab give them to me so other people can take them if they don't know how to get them. :) That's how I got the pair that I have in my closet, before I knew how to do it myself. :D
Well, I wish I'd known that a lifted pixel, because then I would have mailed them to you, rather than dropping them near the quarter sign on the 5400 block of Lorme Rush Quarter.
If you want, they may still be there!
if, when you are done having the crab listen to your music, you flatter and then hug the crab, he takes back his headphones and gives you a crabato juice. That is at least useful, and I leave 6-packs of crabato on my neighbor's doorstep, every once in a while.
They are good for hoarding, and figuring out how to get them in the first place... Sort of an unofficial trophy. I wonder if Tiny Speck didn't have another purpose in mind at one time.
@PulaPulaBompa the headphones only stay in your bag while the crab is listening unless you click "Drop" on the item menu. The crab gives you money if he hasn't just heard what you play to him.
When the crab asks you to play something for him, and you click on a music block to play, he gives you headphones which go into the first open slot in your inventory.
If you leave them in your inventory, the crab takes them back when they are done, giving you currants and XP based on how familiar the music block was.
If you drop them on the ground, the crab gives you Currants and XP based on how familiar the music block was. You can then pick up the headphones and keep them.
If you come up to the crab and flatter, then hug the crab, you get a can of clamato juice. This has nothing to do with playing the music block.