Look at the two examples below:
1) This denunciation of materialistic pleasures invoked by the ever-expanding Industrial Age was a constituent of Transcendentalism, a philosophical movement concurrent with the second wave of Romanticism, which culminated in a similar esteeming of nature's prowess and anti-collectivism.
2) This denunciation of materialistic pleasures provoked by the Industrial Age was linked to Transcendentalism, a movement concurrent with the second wave of Romanticism which privileged nature's prowess and anti-collectivism.
The principle idea of these two sentences is the same, but the first sentence is filled with unnecessary vocabulary. The second sentence is far more succinct, but is by no means minimal and unsophisticated. It strikes a balance between clarity of expression and salient language use.
So really, it's all about utilising complex language appropriately.
And of course, it's important that you write much more simplistically in terms of language but still answering the question well with sound textual analysis and structure, however if you nail that aspect, flair will definitely assist you. But even then, as I pointed out in my previous post, if your writing is all over the place and the point you are trying to make is either wrong or simplistic then throwing in large words probably will not save you. You also need to realise that when it comes to essays, most people will have roughly similar arguments depending on the texts they're given. In that case, to differentiate yourself it becomes necessary, to some extent, to not just make a clear point that the vast majority of people of making, but to make it with some sophistication and nuance which may or may not come from language.