I don't "like" the expense of tournaments, but its well worth it. Skiing with the same people every weekend is fun, but I need more. When it comes to tournaments I like the butterflys, excitement, frustration, joy and fun atmosphere. You just don't get these feelings from skiing at the lake on the weekend.
I think this is what separates us from the folks who hit the lake, drink beer, and pull themselves around on a tube. We need more. Tournaments are what give us this.
As far as nationals, its more for the experience than the placement for most of us. But for those of us that live and breath this stuff, its like being a kid in a candy store.