You know, words are important for an author. The most important thing, in fact. It's what makes us writers, after all. But if the choice of words that is important; the order, number, and tone are often even more so.
This was no where more apparent to me than when I did my PhD. Novelising is one thing, academic writing another. I found 'tone' to be easy to come by. It was something that either comes naturally or you have to learn it (which is entirely possible). It wasn't hard to hit the right tone, for academia. I'd done a lot of academic writing before the PhD, and it came back naturally. It is mostly characterised by a formality not found in prose and a more traditional (and larger) vocabulary.
Voice is also, like tone, something that can come naturally or must be learned. It is harder to learn. I know people who have never figured it out. That's alright, as that's what editors are for. But when it comes naturally, it certainly makes writing easier. 'Voice' is no where more important than in a PhD. There is an academic voice that is needed, just like there is in academic tone. But within that are other voices: the active and the passive. They each have their place. Many people will say a research paper should only use active, but passive is important, and combining the two at the right point in time, even more so.
But this is also important in prose, and passive voice is not good for a novel. Time and again you will hear 'take it out!' shouted loud and clear. Novelising is active. But passive has it's place too, in historical books, in reflecting, and character introspective. Don't just throw it out and be done.
And although vocal and word order is important in academia, it doesn't make or break it I've found. Going over board is as bad an idea as being too simple. But in prose, sometimes, that one word can change an entire scene, or explain a character trait. Or have everything click. Word choice is hugely important, and how those words are presented, even more so. But that is, after all, why words are so important to writers and why they call to us from out in the wide universe, demanding to be put on paper. And it is, in the end, why we write.