Shotokan karate stances and movement
Stances, are transient things that have become formalised for students to learn. They can't generate power when static, something has to move, legs hips, shoulders etc. As an experienced karateka you're constantly moving from one through another and through another when sparring or fighting.
As beginners we learn the stances so that our body becomes accustomed to how it feels when we need to be in a particular position to deliver a particular technique.
Gradually through practice the transitions become quicker. Think about a golf swing you could take 4 pictures(addressing or eyeing the ball, swing back, hitting the ball, follow through) and show how a golf swing is made, but it has to be a fluid movement for it to work.