I'll be stunned if the B3 doesn't provide much larger prizes. If the B3 prizes are more, the national cup becomes an afterthought. Even then, it becomes an afterthought compared to the league anyways. Plus, you can be a lot more creative with training playing scrimmages then trying to win cup games.
Main motivation to win the national cup becomes getting into the B3, so if they B3 prizes aren't substantial, there's even less incentive.
"Well, no ones gonna top that." - http://tinyurl.com/noigttt