Clear language is nuanced language
I used to hate vocubulary quizzes when I was younger. Mainly because I thought it was a waste of time to learn an obtuse word that could be explained using words already in my lexicon.
Now I realize that using a more appropriate synonym (and discerning the difference in semantics) makes you’re communication more clear, not less.
And that a handy thesaurus (or usage dictionary) can do wonders for both your writing and you’re thinking.
Certainly using words for the sake of sophistication is a disservice to language and your reader. But nuanced language, making distinctions (and improvements) to how things are sorted and said, brings as much clarity to composition as it does to mind.