If the Mayor is the Seer, they want the Village team to guess the Word. Because they don't have a Seer guessing to help them out, they might want to choose a slightly easier Magic Word (a Seer-Mayor will be given a 50% chance of word choices one difficulty lower than the currently selected game difficulty). Of course, if the Word is too easy, the Werewolf might figure out that the Mayor is the Seer.