But isn’t that the whole point of the exchange shop? to exchange your unwanted items for medals to later buy the items that you weren’t lucky enough to get? Just because they added the option to buy tradable items on the market and exchange the medals yourself doesn’t mean that was the primary intention.
Wings and character effects are different, its pretty obvious that they won’t ever be added to the exchange shop, and I’m pretty certain everyone knows that and those who are asking for it are mostly just memeing.