There is also an interesting phenomena that when using a tripod, I, as well a most of my fellow portrait types, found that with the tripod you saw things and could fix them, that you would very often miss shooting hand held.
It was the fact of holding, balancing and looking through a viewfinder all at once, that very often made for, clothing issues with the subject that were missed, background issues that were missed, and imprecise cropping.
This was with medium format.
So it could be argued that a tripod holding the crop, holding the perspective and the subject, allows the photographer a far greater control of the shot. As well with portraits, the ability to see the subjects face the instant the shutter is released, (SLR), because you aren't looking through the viewfinder.