The point of a laser alignment tool such as the versalab is that it guarantees that the laser is perpendicular to the base of the versalab and therefore perpendicular to any flat surface you place it on. It does not point straight up through gravity like a plumb bob.
The name of the game with aligning your enlarger is getting parallelism between your easel and the film plane and the lens axis perpendicular to those parallel planes. The planes could be 1 deg out from a plumb bob, but providing they are parallel then that is what you want.
That ball you are looking at is aligned using a normal spirit level. The laser just points at 90 degrees to the spirit bubble if it has been set accurately.
Therefore it is only good for gravity vertical like a plumb bob. The way it seems to work is by moving the ball in its holder until the spirit level bubble is centred and that tells you that the laser is pointing straight up. But only for the direction the level is pointing. But what if your baseboard/easel is not level? Well straight up won't be perpendicular to your baseboard/easel which means you won't get parallelism with the negative plane. So you will have to set your baseboard with a spirit level.
i.e. its no better than a normal spirit level because it doesn't work by giving the perpendicular axis to the surface it is resting on. And it is set using its own spirit level so it can't be any more accurate than a spirit level.