I get that about the autobid, but actually all conferences don't do that.
The ACC is like the Big East.
But the B1G crowns the tourney champ as "the B1G Tournament Champion" and the regular season champion is "the B1G Champion."
This is in keeping with the fact that the B1G was the last of the big conferences to even schedule a tournament; at the time they didn't want one, they were dragged to it; and once they allowed a tourney to happen, they made sure that only the regular season champion would be considered THE champion.