Interesting! I thought the concept of pure water is that it absorbs the dirt, minerals, salt etc. That the water is somehow "hungry"
Then you rinse away this dirty water with more pure water to leave a clean window
Maybe I've got it wrong, but this is how it's being promoted.
The salt doesn't seem to form crystals like table salt, more of a thin film. If you apply any water to it, you
will dissolve at least some of it, polluting the water. Surely better to make sure you dissolve ALL of it, then rinse. Then, perhaps you would stand best chance of leaving the windows spot free :-/