Bruno I have done renders that prove otherwise.  In fact the manual even says to try this as a technique for procedural terrains.

It will only look like jaggies in the terrain editor view, but in the render view it will look awesome.

This technique has been discussed often.  The only thing different now is that there are 2 mapping modes (it makes more sense) one for the material and one for the procedural terrain function output.

If you want you can have world mapping for both and have the same function drive the material and the terrain.  Of course the function would have to be copied over to the other control.