No, it's just a dedication to pure relational algebra. Nulls introduce "three valued logic" into your code/sql. A nullable boolean column can contain 3 different "values" instead of two. True is not false, true is not null, false is not null (and null is neither true nor false). Or in a nullable numeric field, you have rows where that column is neither greater than zero or less than zero.
On the other hand, even if you eliminate all nulls, you still have to do some three-valued logic ("A join B on B.is_something", "A join B on not B.is_something" and the "anti-join": "A where no B exists"), but only in the context of joins.
It feels a little like rust's Option type. If something in "nullable", these are tools that forces you to deal with it in some way so there are fewer surprises.
On the other hand, even if you eliminate all nulls, you still have to do some three-valued logic ("A join B on B.is_something", "A join B on not B.is_something" and the "anti-join": "A where no B exists"), but only in the context of joins.
It feels a little like rust's Option type. If something in "nullable", these are tools that forces you to deal with it in some way so there are fewer surprises.