Putting Your Foot Down
In Vienna, I would say that about half the cyclists I saw had their saddles adjusted so that they could touch the ground with a toe. Based on the pictures here, this seems to be the case in Copenhagen as well. When riding in cities with frequent intersections and stop signs, it can be tedious to get on and off the bike every 3 minutes. Being able to put a toe down makes things easier.
this video of Dottie starting and stopping on her bike to get a better idea of how this works on a Dutch bike.
Adjusting your saddle so that you can stop with a toe down is mainly about convenience. Some cyclists prefer this method, while others feel that not having their leg 100% straight on the downstroke robs them of power. How do you stop in traffic when cycling for transportation? And is it the method you've always used, or did you develop it after some trial and error?