I've lost over 20 pounds, and I have a serious caffeine/ diet anything (i.e, sweet tooth) addiction. In the end, I really think it is not about what you consume-- it's how many calories you take in, and how many you burn.
The whole, caffeinated beverages don't count as water thing never made sense to me anyway. According to most diet "guidelines," you *have* to drink at least 8 glasses of pure water (some diets, i.e., WW allow stuff like crystal light/ milk, etc.). So, I can't have coffee as water. Yet, coffee is a liquid going into my body. However, the diets don't have any rules against caffeine pills. So, under that logic, I can't have a cup of coffee and count it as water, but I can have a cup of water, and take a caffeine pill with it, and it's ok. Doesn't make sense to me, and doesn't make sense to me in execution (I've tried no caffeine-- didn't lose weight any faster/slower-- no variation at all).
if it works for you, though, great!