Radiator Question for the Guru's

In the early days of my making believe I was an auto mechanic, nobody ever stressed the using of distilled water with antifreeze in the rad..
I know my Father use to take the garden hose and mix it with the antifreeze. Whenever I bought a used car I would look in the rad and see the white scale build up in there, which meant having it boiled out or replace it. For the last 40 years I've been using distilled water and never see that scale build up in any of my cars.