Repeatable observations of some effect that one knows one wants to happen in their tank is a fine reason to dose something to NSW levels.
Even the hint that it does something that you want may be reason enough to dose something to natural levels just to hedge your bets.
The first is typically lacking for anecdotal reports of benefit from something like lithium, barium, or rubidium.
That said, the hobby is filled with misinformation. High or low levels in a skeleton are especially meaningless. In many cases, it is just an indication of the amount of that chemical in the water, and its propensity to substitute for calcium or carbonate in calcium carboante.
For example, there is a lot of very well studied strontium in coral skeletons. There is an equal amount of very well studied strontium in simple abiotic precipitation. It is studied so much because the amount incorporated is temperature dependent and is looked to as a historical indicator of seawater temperatures. There is zero convincing evidence that I have seen from any of these studies that it is useful to the coral to have strontium present, and plenty of contrary evidence based on reefers with low strontium having fine reef tanks.