I came across this issue, using the $dataValue with line or area charts doesn’t print any value, although in the Tooltips macro description under the Applicable charts it includes the exact same list with the $value macro which works fine with line and area charts.
Using "plottooltext":"<div>$label<br/>$seriesName:$dataValue</div>" via the chart or "tooltext":"<div>$label<br/>$seriesName:$dataValue</div>" in the individual dataset both work perfectly fine with bar("column") charts but produce a empty string for line and area charts. One has simply to change the graph type with renderAs to observe the above results.
The lack of this feature is a major work load issue, as it forces you to virtually transfer and rewrite all your customisations regarding your data on the specific chart tooltip, rendering the commands regarding decimals, separators and any other number formatting pointless, as you will be forced to manually format your data upon passing them to your dataset.
Please advise, as to if there is a workaround on this or if I have misunderstood the usage of the specific macro. In any case thank you for providing us with this great tool.