Though I wouldn't use these myself in front of a group, I think having sets like this on hand so children can do their own, completely open-ended storytelling would be wonderful in the classroom or library setting. You could of course use a set that corresponds with your storytime theme, but having random sets available allows the child to lead, which is always a benefit in my opinion.
Buy this set at my Etsy shop: https://www.etsy.com/shop/FlannelBoardFun
Flannel Friday is being hosted this week by Kim at Literary Commentary! You can also find tons of ideas at Flannel Friday's Pinterest Pages, the Flannel Friday Blog, and Flannel Friday's Facebook page.