The problem with scheduling the matches over the 3 days is time and space. It takes the hotel time to remove the chairs for the clear area for the board (and it's a typical policy that only hotel staff can do it). So that's and half-hour to and hour before and after the match. And given the size of the event, it needs to be held in a bigger room, so options on where to play it is limited... if you look at last year's schedule, Live Events was a pretty busy room. (Outside is not a good option - where is the space? Security? And rain?)
Then there are time conflicts - Saturday, people are still in reg lines. Sunday, Cosplay. That is one of the reasons for having it on Monday. Yes it takes a chunk of time, but it's also when we have the most time available for it. The event deals with a lot of people - 16 people to a team, making sure everyone is there,knows the board. And getting people in the room... squeezing in as many people as possible to watch took time (hopefully, next year we won't have to turn people away).