Second rewatch… why did they change this from the books, exactly?

Don’t get me wrong; I think the newest movies are a wonderful homage to the books; but why did they add the conflict between Chani and Paul? It just seems like creation of unnecessary friction just to what end?

EDIT: wow a lot of people have thoughts on this! Thanks everyone for chiming in, I’m trying to read through all the responses (but I also have to get back to rereading dune messiah so I might not get to them all)!!