Its still empty calories. If your trying to lose weight, and eat say a 2000 calorie a day diet, 2 waters at 125 each os 250 calories. 12.5% of your daily food allowance will be water. Id rather the enjoyment of eating the food, let alone the cost of 2 a day.

If your trying to adjust your lifestyle, go ahead and try it if it weens you off soda. But try to keep adding green tea. Once a day, then eventually as you grow a taste for it start replacign your expensive flavored water with it, you'll end up with a flavored drink that has zero calories and is actually good for you.