It is often easier to do the windows trad if you can position the ladder on the frame. E.G If you have a large double window you can position it on the frame in the centre and then you are able to reach both sides at the same time. The other advantage is because you can place the ladder half way up the window you are able to have an improved working height with no need for potential over reaching to get at the top windows. From a safety point of view a pointer will also allow you to maintain the 3 rung rule (no standing right at the top of the ladder). The other advantage is that you can (Disclaimer - this is up to you if you do it!!!) also position the ladder onto the side of the window opening. Sometimes this can be useful if the ground isn't level facing straight at the window but is at an angle if you get what I mean! Basicly they offer all the benefits of a usual pointer but up a floor. When I was Trad thats all I used to use. At first it can seem a bit strange and you might think that they wouldn't be stable but Imo they are just as stable as normal ladders. In fact I remember once the ladder slipped on decking and because it was a pointer it slipped down the frame and the rubber bit at the top came to rest on the sill, The bottom of the ladder slipped out until it reached the bolts that hold the clips (for extending it). The ladder locked out and I was able to get down (well dodgy!!!) It was a VERY VERY lucky escape. To this day I believe if I had been using a standard ladder that would of been a fall. In fact a week later another window cleaner in the area had the same thing happen and his ladder slipped on decking only he was using a normal ladder. Down he went. Made a right mess of his face - He broke his jaw, a cheek bone, his nose and if that wasn't enough his ribs and a leg. Very nasty.