"For living-room players, Scrabble is about language, a test of vocabularies. For world-class players, it’s about cold memorization and mathematical probabilities. Think of the dictionary not as a compendium of the beauty and complexity of the English language, but rather as a giant rulebook. Words exist merely as valid strings with which to score points.
A Scrabble board after two top players are finished playing on it might look, to the uninitiated, as though they had played in Martian. Here’s a taste: In a single game in last year’s Nationals, Richards played the following words: zarf (a metal holder for a coffee cup), waddy (to strike with a thick club), hulloed (to hallo, to shout), sajous (a capuchin, a monkey), qi (the vital force in Chinese thought), flyboats (a small, fast boat), trigo (wheat) and threaper (one that threaps, disputes).
Top players tend not to be novelists or poets, but more often computer programmers or mathematicians."
https://fivethirtyeight.com/features/what-makes-nigel-richar...
Sidenote on replacing Q and Z: "Qi" and "Za" are common and useful ways of using q/z which also readily support replacement. In my experience, this is the first "rules change" that one encounters when going from casual Scrabble/Bananagrams/etc to something slightly more competitive. Enabling or disabling these two two-letter words in particular has a huge impact on the game.
https://fivethirtyeight.com/features/how-qi-and-za-changed-s...