This is neat. I had a recent need to do something similar, but ended up using Grist CSV Viewer[1], which I think is a bit more feature complete. I had ChatGPT create an HTML file that would let me paste the CSV instead of loading a specific file and it worked pretty well while being more convenient than loading the CSV into Google Sheets or whatever.
Thank you for sharing this! I‘m using pivottable.js but I noticed that it‘s sometimes hard to understand by my colleagues. Will Grist definitely give try.
[1] https://www.getgrist.com/csv-viewer/