Timing for the game loop and accessibility. 5 letters gives enough options without requiring the player to have access to a lot of guesses to have any hope of

Timing for the game loop and accessibility. 5 letters gives enough options without requiring the player to have access to a lot of guesses to have any hope of winning, and gives the game a short playtime. It's built to be quick to play. You can play it on a commute, or dip in a few times throughout the day. You wouldn't have that progress visible to players with a larger problem space. Tangentially, you'd also wind up having to lean more on "technical" (as in scoped to a particular domain, not technological) language in order to fill the list. That limits access to those outside of that field of study.