The joy of card formats is that you don’t have to play the whole time, you can even miss whole days. If you’re really good you can qualify in relatively few attempts, if you don’t care much about where you finish you can play your three or five cards or whatever your time or money limit is and then go and get on the beers. Long qualifying gives you that choice, as well as the fake internet points
Very few (if any) people will be sweating out the entire 20 hours of qualifying. It’s probably counterproductive, and definitely very expensive, to do that.
