What is the point of prospective buyers asking me to trade my Unusual to a friend first?

Recently, I unboxed a new Unusual Hat, and a couple of people have tried doing this to me:

Never tell your password to anyone.

ME.: hello

THEM: hey

THEM: how much for your unusuals in buds or keys?

ME: for the Janesary (with new effect) I was looking for around 2.5 buds

THEM: okay can you wait 5minutes ? il lget the buds first

ME: k

THEM: can i ask a rpoof before i get the buds?

ME: ?

THEM: do you have a trusted friend?

ME: you are the second person to ask this. I dont feel like doing this so I dont add more IDs to the list

THEM: can we use your trustred friend to hold your items until i get the buds?

ME: why does it matter

THEM: coz ive done this before i buy the items then they cancel our agreement.

ME: i dont have anyone else who wants to buy it

THEM: you can trade to your friend now and tell him dont give to me unless i get the buds

ME: i dont plan on doing that. I don't want to add more ids to the main list

THEM: so whats the name of your friend?

ME: his username is IDon'tPlanOnDoingThat

THEM: k

UPDATE

THEM:?

ME: ?

THEM: so you got a friend now?

(I will update that if he adds more).

What does this try to accomplish? I don't understand at all, but I don't plan on doing it.

They're trying to scam you.

It's a common scam tactic to try to impersonate one of your friends (name and avatar) to give the unusual to it, at which point they have the unusual and run off with it.

Usually, their alt account is already on your friends list (previously traded with you).