As well as them seeming untradeable it means they are only ever worth their face value, but as soon as you trade them they're gone. So a Coin Suitcase, worth 1500 Credits at face value, but it doesn't matter as if you trade it, it's then out of circulation.
I think they'll probably stop Market Place trading on currency items - if not then they might have a level of rarity about them if they don't change to purse Credits when you buy them. Although if they did change to purse Credits when you buy them from the Market Place it's just incredibly pointless as you need to use those Credits to buy it anyway!
The way limited currency works, and has always worked is that it's available for a limited period of time and therefore gains value - they are just ruining that, yeah do it for Catalogue currency, but don't extend it to limited ones - the limited ones could actually be worth something! I would be really annoyed if I had bought a currency for over it's face value, because now you're just going to trade it for the face value which isn't fair if you bought it for more.
Goodbye 48c Gold Bars, as the person buying the Gold Bar gets the 2 Credits anyway - they need to remove the tax if they're doing this, it's unfair and stupid if not. What if you sell something in a 1 Credit shop? You can't then use that in another shop, it's just reducing the amount of trading that will happen because we won't be able to afford the exchange rate eventually. I can see Market Place values increasing for some items, those that you usually buy in shops because why spend 2 Credits for a Bronze Coin when for example, I could buy a Corner Plinth for 1 Credit (2 with commission) in the Market Place and save a lot of hassle finding another Credit for the exchange.
They could have asked players how they could improve trading, or what we would like to see, but no, it's all about their gain again.