I think this is by design. The idea is you bring your data in the expected format (using spreadsheets, or pivot tables, or observable, or pandas), and RAWGraphs will make one of a few common modern visualisations. The sort of stuff you would hope Excel/etc. will have out of the box someday.

Observable is definitely more of a power house :) Out of curiosity, do you have any templates you'd be willing to share?