My undestanding is the idea it simply ataches to a wfp so for you try to break up sods with the small hook/spike on the end whilst wetting them and/or maybe flush gutters and downspouts through afterwards.
Not tried one myself yet but the hook/spike looks a wee bit small and the jet would probably not give any decent high enough flow rate to flush gutters or downspouts through properly so in all looks a bit of a none starter to me.
I could be totally wrong but without seeing a vid of it in action tackling sods, unblocking downspouts, flushing gutters through etc to convince me it works well then I don't think I would buy one myself.