> This gets less ideal when you want to implement some kind of hover tooltip that shows that value at a particular point.
A data value doesn't have to be identical with the value used for plotting purposes. Haven't used Apache Echarts but this separation of concerns is trivial in D3, for example.
This comment so beautifully distills the difference in philosophy between D3 and Echarts.
Charting libraries like Echarts provide a few stock visualizations and a handful of knobs to turn. If there's not a knob for the parameter you wish to adjust, you're out of luck.
D3 provides instead a visual grammar: a toolbox for building your own visualizations.
A data value doesn't have to be identical with the value used for plotting purposes. Haven't used Apache Echarts but this separation of concerns is trivial in D3, for example.