To explain the history a little bit (as a Korean):
Hancom's Hangul software was popular in Korea in the 90s because of its splendid Hangul support (Word wasn't that good at it back in the day). So it became a de-facto "standard" for Korean documents. But the problem was, piracy was really rampant at the time, because it was before online DRM protection technologies came into light. (They've tried hardware DRM, like the serial port dongles, which eventually were cracked.) They almost went bankrupt, up to the point where Microsoft was thinking about buying them out (there are a lot of conflicting info about this in the internet, so I don't know exactly what deal might have gone through)
But then, when Koreans learned about this imminent danger, they launched a national campaign to save the company, and raised over $10 million for them. As for why this was possible: nationalism was pretty strong back in the late 90s, partly because of Korea's IMF crisis. (If you want to read more about the Korean economic recession and how people responded to it with activism, read more about the Gold-collecting campaign in 1998 [0]) Because of this, Hancom was able to recover and still be alive to this day.
Nowadays more and more Koreans are using Word these days, but Hancom's software still has lots of uses, especially in the government. The Hangul word processor had some unique characteristics other than just language support: most notably it was one of the first word processors to have nested table support. Because of this, many Hangul documents have layouts made of nested tables (I know some people at HN would be utterly disgusted with this, but this has many benefits: you can have total control of your document layout, and it's good for making documents with dense information such as government forms.) This is why Hangul documents cannot be simply converted to Word; the two have very different conventions about layout in general.
To conclude, reflecting this as a Korean (and an avid Linux user), I have both good and bad feelings about this. On one hand, Koreans were forced to use a proprietary, non-free program to open their documents, including important government stuff. This also sucks for Mac and Linux users (The Mac version was horrible the last time I've used it, and I couldn't get the Linux version to install on Arch Linux). On the other hand, if Hancom wasn't alive, then Koreans would be forced to use Microsoft Word with subpar Korean support (because Microsoft wouldn't really care about Korean language support unless there was competition). While I have mixed feelings about Hancom, I really hope that they would provide good support for Linux users in Korea.
[0] https://en.wikipedia.org/wiki/Gold-collecting_campaign