I would like to see an efficiency comparison of similar applications, because I have come across several in the past. Also for Chinese or Korean.
I thought modern Korean just used Hangul, which is trivial - https://ryanestrada.com/learntoreadkoreanin15minutes/ ?
To give an example, I’ve just watched episode 12 of “Strange attorney Woo”, and one of the character talks about the two different hanja that make up 사 in 변호사 and 검사. A lot of the older generations still use this kind of comparison to make a point about nuance/history of a word.
But if you talk to younger generations, they talk predominantly in internet slangs and have no clues about hanja.
Not sure if you can read Korean but here is the link that talks about differences between the two hanjas: https://m.ch.yes24.com/article/view/33205