Still, for WHM it's preferable to doing nothing.
To kill boredom yeah, but in terms of party contribution... no, it's the same thing. The (small) numbers may disagree, but if you look at the bigger picture, a couple of minutes off a run means absolutely nothing. If someone's gotta pee, or your phone rings, or whatever, that time you saved by dpsing is already gone. You're not making any tangible difference, it's all theorycraft circle jerk.