From an ecological standpoint, natural materials have the 
advantage that they generally don't require much energy to 
manufacture or even transport them. This savings in energy 
will likely diminish the amount of greenhouse gas (CO2) 
that is emitted and also the amount of fossil fuel 
consumed. From an aesthetic/emotional standpoint, natural 
materials feel much more, well, natural. Technology is 
always behind the scenes in our modern world, and I am not 
one to spurn its use when appropriate. I just feel that one 
should look to the simpler, natural solutions first, before 
employing more technological ones.