Low sodium means reduced salt. Salt doesn’t just add a salty flavor to food, it also enhances many of the flavors already present. Therefore, reduced sodium often means less flavorful. Hence the cardboard flavor reference.
Fingernails growing faster might make sense from an evolutionary perspective. Fingernails and toenails evolved long before people ever were. Many mammals that proceeded us but were in our lineage had four limbs with multiple digits on them. The front ones were used the most for digging for food as they were closest to the mouth. Faster growing fingernails would be a significant survival advantage.
We had a cat that we gave regular baths to starting when she was a kitten. She tolerated the bath because she loved getting blow dried afterwards. So, yes you can bathe a cat without getting clawed if you start early.
Low sodium means reduced salt. Salt doesn’t just add a salty flavor to food, it also enhances many of the flavors already present. Therefore, reduced sodium often means less flavorful. Hence the cardboard flavor reference.