Bringing someone as high-profile as Villeneuve would absolutely bring more credibility to this project, especially if Blade Runner 2049 is a hit.
Dune is far from a known property at this point, even after achieving cult-classic status.
The books were extremely popular, but so far any live-action attempt has had a difficult time at managing all the mythology that Herbert brough to the books.
If and/or when Villeneuve does join, the project could really pick up steam and begin casting to capitalize on the buzz that is attached to his name.