Much of this works great but I do not receive the required authentication code email from Steam. I do receive the needed authentication via email when logging in via web browser or the Steam app (Linux), just not when using this script. My account is a Partner account which requires Steam Guard and so I cannot remove it even temporarily.
Also, the CSV file of keys lacks games from the past few months -- I have not searched to see how many are missing.
It does look like it was successful at redeeming my "Choice" games.
Is this script still working for other folks?