Upsight is similar to insight, in that you suddenly see something you didn't see before. The main difference is where you were looking when you saw what you saw.
In insight you are looking from the exact same place, the horizontal plane, and therefore the insight doesn't make a difference, it adds to your useless knowledge.
In upsight you are looking from the vertical plane, from where you can only see the fact, and none of the interpretations that you were stuck with on the horizontal plane.
Getting an upsight is a transformational event with inescapable consequences: you will never suffer again from the interpretations, like before.