If it doesn't exist on exchanges it should still work fine with the internal market. Even if your goal is to buy HDB using funds from an exchange or external fiat, you can buy HIVE and then trade that for HDB using the internal market. There really only needs to be one path to external value for it to work, the rest is gravy.

As for Korean pumps, I see it as a stress test. The stronger the stabilization mechanism, the less successful pumps will be and that in turn reduces the appeal of trying to pump it at all.

One should not expect perfect stability though. Even the granddaddy asset of them all, USD, has value fluctuations due to market disruptions and speculation, sudden large ones at times. That's inevitable. What is important is that relative stability is maintained.