Makes the footage blurrier than film would, but it gets you an extra stop of brightness without any added grain from gain. It's the right choice under some circumstances but not all.
You don't have to go all the way to 1/25th though; you can use the syncro scan shutter and choose anything between 1/25th and 1/50th, so you can choose how much brightness you want vs. how much blur you can accept.
