Please justify, why do not use dispersion fillers for smoothing substrates, if metallized or plastic wallpapers are not to be applied

Metallized wallpapers and plastic wallpapers create a very tight coating. The water contained in the glue mass cannot evaporate through the wallpaper, drying is therefore very difficult. The putty remains wet for as long, until the water is drained through the substrate layer. Dispersion putty, due to the method of production, have a higher content of cellulose ether. This causes their strong saturation with moisture. For this reason, despite the smooth putty surface, inequalities are created, which then stand out under metallised and plastic wallpaper.