Fan I think part of the reason I went with the Big 12 tourney is because it's important for teams once they get a couple rounds into the tournament. Additionally some teams view it as their chance to get into the dance, or with soccer a higher profile and a chance at other tournaments. Some teams really don't put their effort into the Cup until they get to the later rounds because it risks their players for post season a bit. So if you're a KSU, ISU, or Texas you might try once you get into the semis or finals, but if you are a lock for the Dance and you are dealing with stuff you might not go full bore in the conference tourney when you are holding for the Dance.
As others have said, this tournament is a bit more important then January basketball, especially once you get towards the end.