Well, I'm not sure about the sense either, but in the past it was this way. Maybe it's different now.
But I have the answer for the league winning bot. As I understood, which may be wrong, the bot team gets promoted and immediately demoted, and his place is taken by whatever team was among those with adequate record and that won the conference. So the human team that didn't win against the bot should remain in the same league.
"BuzzerBeater, the best simulation game of real market economy" (with a cool live basket viewer).