Every animal including us crouches when they sneak or prowl. You are able to test the ground before setting your foot on a stick for example. Also, aim is better for archery.
I thought standing tall and rigid as possible was best for aiming in archery, crouching would be really awkward. Then again, I have an imagination and Bethesda doesn't have to spell
everythig out or hold my hand for me to know how to play a video game.
What is next? People are going to complain that we stand too many times when we eat, and not enough people are sitting down when they eat or drink?