BlackBogey: So far, the only thing I'm really finding the vertical dots helpful for are that you might discover that a putt might say -3 for elevation, but if you look at the vertical dots you might notice that it's -5 at the beginning, but then actually +2 for the few feet, which would indicate you might want to hit it a little harder and play a little less overall break.
That's part of it, but not the complete picture.
A lot of times, you will have an offset putt... for example, one of those putts like on Kiawah where your avatar (and the grids) do not line up squarely with the hole. In those cases, if you look at the vertical dots, you will see that they move in such a way that - because of their movement angle relative to your putting line - they either add to the break or subtract from it. I suspect that probably 99+% of the time, players that don't look at the vertical dots are the ones complaining bitterly and saying things like "That putt showed break but didn't break!" or "That putt didn't show anywhere near that much break!" or "It's VEM!"
As for using the vertical dots to determine which (single) horizontal dot to use to determine your overall putt break, well, that sounds like a shortcut to me. If it works for you... great... but personally, I look at all the dots (both horizontal and vertical) on every putt between my ball and the hole to determine what the ball is going to do.