I am interested in practical experiences and feeling you had using them/watching kids use them.
It is nice for makers as you get to build it and can modify its shape. It is a basic arm but with 6 motors you get more cool movement out of it. And it is controlled via a RPI and is all open source which I like.
But for kids I don't know if the age target is suitable, the project targets education https://www.poppy-project.org/en/education/ with visual programming and activities but I never tried..
Teachers also have a pedagogical mission. They are supposed to teach social values. So you might want a robot with an AI good enough to analyse group behavior in real-time and intervene appropriately.