then again it supposedly tastes bland, is more expensive than tap water (provided your tap water is safely drinkable) and why even take the risk?

Coffee.

Do you find that your coffee maker gets slow over time as it gets clogged with calcium buildup? The you have to run vinager through it and stink up the house to clean it? Use distilled water, and it won't do that anymore. As long as your entire liquid intake and majority of your calorie intake doesn't consist solely of coffee, it won't cause health problems either. You can even put a pinch of salt into the coffee basket to replace some electrolytes and make the coffee taste more like coffee.