My Take
I dislike multiple-choice questions in general, and Kahoot works best with that sort of format, so it kind of forces me to put complex concepts into small questions with limited text. However, the engagement makes it worth it, and it CAN be used to teach complex concepts DURING the game when students are at that heightened engagement level.
How I Use It
I have only used Kahoot to help students review for tests. It allows teachers to create a gameshow-like experience for students, including music and a scoreboard. Kids get really excited and enjoy playing!