Such a cool way to continue coordination development. This exercise is great because it adds movement with ball control and that ball control is out in front of the body (as much as possible). We are adding the element of tactics (basic tactics but tactics nonetheless) and they need to think about where to score and how to position themself for the goal.
Overall coordination and skill development
As you and they desire.
Play just a little bit past boredom. If you stop the moment they start to lose interest you will delay resilience building, and overall grit development. By going a little longer you also extend their attention span. The idea is to avoid making any drills or training with 4-6-year-olds feel like a chore or so boring they never want to do it again. It’s a balancing act and that is where the art of coaching is so important.