Thomas Mann did that (among other authors). He used to read his work to his family. Just look, how complex and hard to read some of his later work still is. And how complex the sentences are structured.
It is no guarantee, if you don't also think simple and clearly. But it certainly helps.
Yes, clarity is not always the goal in writing, especially fiction. I can imagine Mann sitting down reading his drafts to his family, who are all staring blankly at the ceiling, anxiously awaiting the end.
I think this is more of a technique to help people recognize when what they have written is bad. All too often do I get a student who is perfectly well spoken and who has obviously edited their work turn in something that is a mess. When you point out mistakes, they are usually like "wow, how the hell did I overlook something like that?"
It can be hard to recognize that something we wrote is bad, because we know internally what it's supposed to say. Something about the verbal and auditory processes in our brains seem to help bypass that though. It's by no means the only thing needed, just helpful.
Thomas Mann did that (among other authors). He used to read his work to his family. Just look, how complex and hard to read some of his later work still is. And how complex the sentences are structured.
It is no guarantee, if you don't also think simple and clearly. But it certainly helps.