Camera control, e.g. taking pictures and recording videos is a function done by the smartphone, not the Tello, if I'm not mistaken. I'm not sure how complex it would be to add those functions to DroneBlock (i.e. routing the Tello IP camera video stream to the Android recorder app and controling it from DroneBlock).
Very nice! I have tried the Scratch Tello blocks implementation on my laptop, but I dreaded having to lug that thing around in the field. The Android CodeBlock app is much neater for that reason alone.