Opening a CSV in Excel means answering the import dialog and hoping it does not mangle your dates. This hands you a real workbook instead. Quoted commas and line breaks inside cells are read properly.
The spreadsheet writer is a few kilobytes of our own code — no million-byte library is downloaded. Your file is read on your own machine and never sent anywhere — open your browser's network tab and watch while you use it.
Because Excel guesses. It turns 0123 into 123 and reads dates the American way. A real workbook keeps the columns as they were written.
Yes — quoted fields, doubled quotes and line breaks inside a cell are all read correctly.
Whatever your browser can hold in memory. Tens of thousands of rows are fine.
Everything here is free and works the same way — in your browser.