Diatomaceous Earth (DE) has been around since I was a kid and originally was promoted to provide missing nutritive factors in an animal’s diet. The missing nutritive factors were suppose to provide benefits similar to known required minerals or vitamins. The definition of DE appears to have strayed over the years. Still today, many believe it is rich in minerals and that its unknown nutritive factors will improve the health of an animal.
Bottom line: there are no benefits, no magical nutrients, and you should not waste your money.