Perhaps i should of also given an explanation for this.
It encourages strong root growth.
The roots are not trying to feed every thing at once consequently you get better stem growth. Don,t try to grow your cucumbers to big at the risk of poor growth to the other fruit.
A TIP. Where possible nip off the tendrils if they have not bound onto your support , if they get to bind onto its own plant or stem of a cucumber it will choke it.
DavyW