The AquaTap does rely on having the brush resting on something to operate and for those worried about a dirty brush resting on the glass after its been cleaned, you just simply rest it below the glass on the frame.
It weighs in at only 70 grams so hardly noticeable on the end of the pole. Yes it could be a lot less fragile looking, it could be made of metal, but it wouldn't make it practical on the end of the pole.