Our sensei goes to breaking competitions quite often and has a few national championships. But we generally do not break in class and he only teaches it to a few people. It is easy to injure yourself if you don't listen an strike right. I hurt my wrist on some blocks once. Being embarrassed and angry ( we were doing a demo at a relay for life event) I struck again. I did break it but hurt for a few months.
I've never had to use it to defend myself but there have been a few instances that I was alert and ready and took a bit to calm back down afterword's.
I have competed some before but mostly just traditional karate. Katas, stances basics. Some weapons and self defense as well.
Occasion breaking, but that is only certain students.
On another note a recently tried soap making.