Yes,
The Lee Hood helps a lot with ghosting flare, (not as common on the 40mm but will occur) and angle sun flare/bright light etc. I use the hood 100 percent of the time on the 40mm, but I am also most times using a CL-PL or ND or both. But even in shots that don't need it, I still keep the hood on the 40mm. The Lee system has only one main drawback, the release of the hood is way too easy to just push off. And if you load it up with filters, it's front loaded. You can easily just brush against the hood and push the whole thing off. I have done plenty of times. I now have a rubber band system, that allows me more security, as it fits over the release knob and won't allow it to back off with pressure to the hood.
I had hoped that over the years, Lee would adapt the same twist down screw lock they use on the SW-150 for the 100mm filter holder (which also is used by the wide angle hood).
Paul C