Its getting the rooster's blood into the pipes that causes the usual trouble though.
You used the term 'descale' - these devices won't do anything to remove any scale that may already be there. The only way to remove scale is to flush through with some chemical agent.
I live in a very hard water area and used one for many years - attached to the mains cold water pipe as it entered the house. This one used a strong permanent magnet - there are similar devices that wrap coils of wire around the pipe but the principle is similar; it doesn't prevent scale but it alters the chemical composition structure of the scale molecules in some way so that it is less likely to stick to showerheads, that water dribble that occurs down the back of the loo etc. It did nothing in the kettle, which furred up in a fortnight, same as before.
5 years ago I forked out and fitted a proper water softener and haven't looked back since.