Anssi,
That's a good remark.
Actually PR renderings aren't always the best solution to present pre-design imho.
Sometimes it focuses too much on things (materials) that weren't yet decided on or weren't thought through.
Often it is better to make a paper scale model or a rendered one, just to show the mass.
On the other hand, renderings can support the concept the architect is aiming for, even in an early stage.
Also, I tend to believe that sometimes arch competitions are won based on imagery, and I must admit some render people can make a bad design 'look good'. So not always a good thing.
Thanks for the comments.