They're great for kids, or anyone looking to get started.
Like Scratch, they work by dragging blocks together. The experience is delivered very well, with videos and lots of explanation.
The Minecraft exercise is good for any kid who's interested in Minecraft. It teaches loops and 'if' statements.
The Star Wars exercise is great too. You control BB8 (the round droid from the new movie) and learn about events.
I recommend doing both exercises, with Minecraft first.