Isn't the entire point of memoizing this to demonstrate you are able to study/grind rather than prove intelligence? Different companies/managers have give me different reasons for the usage of this style of interview but it was usually to 'assess ability to get through rough stuff' and 'assess cognitive abilities'.

Idk anymore either and I refuse to conduct these interviews. I generally prefer somewhat realistic problems that are multi-disciplenary but have ties to real world applications related to the role.