Short ruler has its advantages: that is to say, ruler is longer than inch, but it also has its disadvantages. Inch is shorter than ruler, but it also has its advantages. Everything in the world has imperfections. This poem is often used to describe that people or things have their own advantages and disadvantages, and everyone has their own advantages and disadvantages.
Snow is three points white, but snow has lost a fragrance to plum blossoms: although plum blossoms are three points crystal white, snowflakes have lost a fragrance to plum blossoms. This poem also emphasizes that everyone has his own strengths and weaknesses and needs to learn from each other.