The modern Korean Hangul script is phonographic, meaning it encodes sounds rather than ideas. Apparently that's good enough, or at least works better than how pure phonetic transcripts work for Japanese and Chinese languages, both of which users rejected that idea. But it was also a result of a relatively recent switch from Hanzi-Hangul mixed script used under Japanese occupation.
Actually, the use of Hanza(Hanzi)-Hangul mixed script wasn't exactly a byproduct of the Japanese occupation. (In fact, Japanese was the official language back then lol)
People started moving away from using difficult-to-type Hanza as soon as the typewriter was introduced. As computerization progressed, the transition naturally continued until Hanza was phased out of most documents. Even so, it has only been about 40 years since Hanza disappeared from everyday daily life.
