@baxter you are obviously bang on the money with the 'water first' philosophy, and you are right to be sceptical of artificial sweeteners (AS), the ones that are man-made chemical AS's are where the real problems can lie (Acesulfame K, Aspartame, Sucralose), particularly in children where headaches and hyperactivity have followed their consumption.
For adults the potential problems seem to be increasing based on our growing knowledge of the microbiota aka the bacteria in our gut. Despite the general consensus being that AS's are safe in adults, the supporting evidence is scarce, and sadly the absence of evidence isn't evidence of absence.
According to Nature.com (one of the most respected journals around) the main concern is more to do with AS's impact on glucose intolerance, through induction of compositional and functional alterations to the intestinal microbiota. Basically, the AS's appear to change the type and expression of gut bacteria we have which may reduce our ability to utilise glucose, in turn increasing risk of developing conditions such as diabetes.
More empirically too, the mouth has sweetness receptors which may be tricked into thinking the body is receiving carbohydrate (and energy) when we consume sweeteners...only to receive no energy at all. By definition artificial sweeteners are not natural so where possible are best avoided. The natural sweetners such as Stevia and Monk fruit are a better option BUT may still 'throw the body off' somewhat with their sweetness and yet non-calorific nature.
So the calories saved when consuming artificial sweeteners may be off-set by the negative effects on our microbiota, which some consider so important that it warrants the label 'our second genome'. Best to look after it then.