Yeh, it's so simple - better than an aqua dapter - cheaper, less problems (aquadapters break sometimes), less dirt up your pole, shorter closed pole length and of course; it's lighter.
I also think it's physically easier too, you can rest the butt of the pole on the ground while closing or extending, rather than having to keep it off the ground. It's only minor, but hour-after-hour, day-in-day out, I'm sure that makes a difference.
Pole hose needs to be a stiff kind of type that'll cut the water flow when 'nipped'. Gardiners yellow stuff won't do it.
I use the soft 6mm (or is it 8mm) yellow streamline microbore.
Yup. Opening and closing the pole is such a doddle and easy and quick and as you say, no grit in the pole what so ever which also means the pole and clamps will last longer.
I removed the flow tap as I now don't need it.
I've also found if I 'whip' the hose around the pole after it's extended, especially for 2nd floor stuff etc, as it wraps around the pole, it catches on the clamp nuts and holds the hose in place.
As for 'nipping' the hose, it's never more than a few inches from your hand.
All in all, life is so much easier window cleaning and as a suggestion, 9.9 out of 10.
Thanks for posting that idea.