I was discussing 成语 (a type of Chinese idiom) with my teacher, and she seemed to indicate that around the HSK5 level, there is a sharp increase in the number of 成语 that the student is required to learn. She also indicated that it was a common complaint by students that 成语 are difficult and tedious to learn, and somewhat boring.
I'm not sure if the following is accurate, but it seems like 成语 are seldom used outside of literature:
...by their nature, formal/literary constructions and so are not commonly used in conversation (unless you want to sound highly educated). Thus this stuff is most useful for diary entries, stories, websites and other written documents.
20 Actually Useful Chengyu (成语)
Hence my question:
Question: Why should someone learning Chinese as a second language learn 成语 idioms?
I gather there's a reason beyond "we like 成语" since there's an emphasis on them in the HSKs. Maybe it'll help me find motivation to study them.