Pros
You sit around and do nothing. Fill out some sheets. Great for if you like children, because you might want to play, sing and dance with them... without looking like a fool to the parents and family in the room with you, who are probably living better lives and working above minimum wage.
Cons
DO NOT bother with this position if you're not a student worker. Student workers aren't even appreciated there, and I'm sure adult workers in this position would not be taken seriously. You are constantly berated and shouted at by parents and SLT even when it's not your fault, or you're following policy. When you get hurt by unsafe work conditions, you get the blame with passive-aggressive emails. Also it's a zero hour contract. Make of that what you will