This may be a stupid question, but what exactly is the concern with erosion in mountainous terrain? I just don't understand what's at stake. Mountains erode. Wh

This may be a stupid question, but what exactly is the concern with erosion in mountainous terrain? I just don't understand what's at stake. Mountains erode. Why should we worry if human activity hastens the process a little? I'm asking in earnest. What am I missing?