They CAN be powerful.
Monica Burns' article title states it well -
"The Simple Power of a Screenshot". Monica discusses a few simple ways specific devices can create a screenshot and also ways to incorporate into the classroom. I, personally, use screenshots quite a bit with the free software from
Techsmith - Jing. It's a simple program that allows me to capture and save any image on my desktop. I can send it to a colleague with a question or send it to myself as a reminder of something to be accomplished. The uses in the classroom would be endless from simple assessments to fun projects.