There’s definite value to simplicity in writing. At the same time, like all principles, people tend to run with the idea and misapply it. There are some cases in which your work demands a certain level of precision that’s only possible using complex words or jargon. Not to mention, writing that’s a little complicated can be a lot more fun! There are several novelists, essayists, and poets who are a joy to read not because they express their ideas as clearly and simply as possible, but because they manage linguistic acrobatics that make us realize there are ways to use language we never thought possible—often it takes some extra work to understand such output.
*: Have never taken the time to verify this myself.