Fit a porcupine sleeve and you would have a formidable cleaner for cladding - no need to waste your money on hot water.
I think it's a brilliant idea, not that far removed from the indoor pad idea from that mega expensive Dutch company. You might even be able to use microfibre sleeves and much finer jets.
For cladding it would soak up those dirty drips that gather after a clean, would also hold tfr or a soap solution longer than a brush for scrubbing conservatory roofs. Biggest drawback would be that it won't self clean like a brush does.