Came across an issue today where if someone changes their username on Twitch, they're treated as a different player by FFBot and they lose their progress.
Worked around it by updating the player database and hire history files to reflect the changed name for the players while the game is closed, but if it's possible to track players by their Twitch UUIDs instead of display names then it might be a good idea to do so to avoid this situation.
I appreciate the hard work Elbody!