The idea is great but sadly there are two problems.
First, the box never ever closed. It became a challenge for my friends and over 5 people tried it but the flaps would just burst open immediately. Brabantia sent me a new cover but this also didn't work. For an outdoor clothes lines that gets dirty a cover is essential. 
Second,  it broke! One of the metal arms just warped when I pushed it closed. Now it is very unstable and still warped.  The line is no longer taut so it keeps pulling the broken arm down.