Doing it to compete and doing it for self defense are two slightly different things.

I did train some boxing in high school and I think learning some basic boxing goes a long ways in knowing how to fight and defend yourself but there's limits as with everything. And with sparring a lot, I don't like the idea of getting punched in the head over and over which is what tends to happen in boxing gyms.

The cool thing about BJJ is you can train and roll all you want in the gym without having to worry about head shots and brain damage. There's still injury risk but atleast your brain doesn't get smashed and you learn some real techniques that work on an actual resisting person.