I can't guarantee that it was usable -- I didn't try to buy anything with it, and for IKEA US to sell to me in CNY they'd have to have an exchange rate set up -- but it was definitely readable.

On the other hand, when I asked the recipient (it was a wedding gift) about it later, he reported that his wife had recorded it as having an appropriate-given-the-exchange-rate quantity of USD, so I suspect it was in fact usable.