I tried the method for Freya but it did not work. First of all nautilus was not installed (only the default files, which is aparently named pantheon-files). Installing nautilus did not help and changing it for pantheon-files just gave me a files window after login that reappeared when it was closed.
Does anyone know how to enable this? I hope Elementary developers will do this by default, it makes no sense to me from a usability point of few to have no use of that big space (and a show desktop button just to look at the desktop picture). It would be great if it would be a simple system settings option under desktop (there is not option for it there either).
Note: it seems some people marked it duplicate, I don't know why and I do not see a link. As mentioned, I tried the Freya options and they do not work and also tried some things myself that didn't work. Remarks about design decisions are not really useful, in my opinion and probably the one of others, that is a wrong decision and that is why I posted the question. Thank you