It just seems very noisy and goes on for hours. I have neighbours on either side who like to do this.
Is it a clean freak thing to do like bleaching door frames? I've heard it's not actually very good for the stones.
I just sweep the paved areas of the garden with an old-fashioned broom from time to time.
(Naturally I tolerate this in the way you have to tolerate neighbours' eccentricities. But this seems to be some new fashion. I can't remember it happening when I was younger.)