The properties mentioned in the article are not really tied to functional programming. - Not allowing null-references can be done with any paradigm. For exampl

The properties mentioned in the article are not really tied to functional programming. - Not allowing null-references can be done with any paradigm. For example with object-oriented programming there really is no reason why it wouldn't work to not allow null references. - Immutability can also be done with every paradigm. The Java String for example is both object-oriented and immutable. I think the paradigm is actually irrelevant. The real advantage is not gained by using a functional programming language. It is gained by using a language that prevents null-references and makes it easy to write and use immutable data structures.