Cool, I think you can scan your existing chess.com games by clicking the chess.com toggle? and enter your chess.com username. You don't need an account to try the tool
Yeah I find the estimate of the radar chart to be quite accurate. I scanned a range of players from beginners, to pros like magnus and hikaru and myself who is in between (2200 elo) and it gets the rating estimates correct. So I think if we work on all the fields it's suggesting we can definitely climb!