Interesting product but I'm 'betting' on self cleaning window technology to become a thing when it's cheap enough.
Yes, it's a thing https://en.wikipedia.org/wiki/Self-cleaning_glass
That said, this gadget would be handy cleaning windows for people who live in multiple story housing.
Self-cleaning glass
Self-cleaning glass is a specific type of glass with a surface that keeps itself free of dirt and grime.
The field of self-cleaning coatings on glass is divided into two categories: hydrophobic and hydrophilic.
These two types of coating both clean themselves through the action of water, the former by rolling droplets and the latter by sheeting water that carries away dirt.
Hydrophilic coatings based on titania (titanium dioxide), however, have an additional property: they can chemically break down absorbed dirt in sunlight.