Vega author here. We actually disagree with the last part.
For visual analysis tools (not just UI charting library), having the ability to quickly summarize data is very useful for analyses (esp exploratory ones).
We are not alone with this design choice. ggplot2 in R and GUIs like Tableau also includes data aggregation as first class citizen in their tools.
For visual analysis tools (not just UI charting library), having the ability to quickly summarize data is very useful for analyses (esp exploratory ones).
We are not alone with this design choice. ggplot2 in R and GUIs like Tableau also includes data aggregation as first class citizen in their tools.