You need a good, not a great vocabulary to communicate effectively. A great vocabulary, one containing arcane words that few know, can hinder communication. Here we have an example, "degust". Never in my 76 years have I ever heard it spoken. Not once in the countless thousands of books, newspapers, magazines, essays, etc. have I ever seen it written. And now that it clutters a dark a dusty corner of my brain (hopefully to be soon forgotten) I will never speak or write it myself. I'm a storyteller, not an intellectual snob. Still, I never let a word pass me by without making its acquaintance. It's a habit that I highly recommend. You never know when it might be something that is commonly used and you don't want to be flummoxed when others use it...