Thanks for your critique of the project.
Initially, we chose Tetris 99 because that was the context in which we had the idea. I won't deny, though, that being able to compare Jeff's performance with human players and see his interactions and victories in the Tetris 99 environment made the project more interesting for us; however, it was wrong to do so in a public setting where the players didn't know that our algorithm was involved and didn't opt in to playing against it.
We're no longer testing or developing Jeff, and if I do any similar future projects I'll choose singleplayer games or private environments where opponents voluntarily test their skills against the bot.