The monks don't meditate to become calm, but to see clearly. Calm is a side effect. Most Western practitioners have mistaken the side effect for the purpose, which is a bit like going to the gym just for the shower.
I had a teacher who once went to visit the Dalai Lama. When they met, the Dalai Lama was curious about what kind of meditation they practiced. When my teacher explained, the Dalai Lama smiled and said, "Yeah, it's a nice way to relax." And then he explained how to take it further.
I often think about this. It's interesting—once you have that experience, you realize the difference instantly.