As the wet end charge demand changes due to variable pulp quality, the DSR performance changes, too, and must be adjusted, requiring operator intervention. This increases operator complexity.
Also, DSR bonds are significantly stronger than hydrogen bonds as would be expected. Creating these stronger bonds reduces sheet flexibility and increases stiffness. A sheet at a given tensile using hydrogen bonding will be more flexible than one using a combination of hydrogen bonding and ionic and covalent bonds of dry strength.