I agree with this. Some writers put in a lot of scientific terms or words from other languages, but I find that it becomes annoying pretty quickly, especially if you need to look it up every time to work out what the author’s talking about. Most people don’t enjoy doing that anyway. Are they going to put down their book (or, to think in modern terms, open a browser on their tablet) when they’re in the middle of reading a story? Maybe if it’s a non-fiction book they might be more prepared to do that, but if I’m in the middle of an exciting story, as a reader, the last thing I want to do is look up a word to find out what it means. I think the KISS principle applies here too. Keep it Simple Sweetie. Don’t complicate things, especially if you’re only doing it so you’ll sound clever.
Totes agree, as a matter of fact I was supervising someone on this recently, and talking about writing for your audience. She was struggling with the difference between academic writing, in which value is measured by the average length of words, and writing for a lay population, in which you write to communicate, rather than show off.