(by JayMen)
Challenges in a hunt break the routine by providing a physical aspect to a mind game. They also impose a shift in tempo to the rhythm of the team.
Not doing the challenge well half way through a hunt will sometimes throw off mentally weak teams. Doing them well raises the morale. Challenges also come in non physical forms as when solving puzzles and quizzes, where a different mental approach is needed.
There have been many good arguments put forth by passionate hunters both for and against the nature of challenges in hunts.