Even if the only thing it gains is confidence, that would still be a good thing. Bullies dont pick on confident kids, they pick on the kids who look like they lack confidence. My first instructor used to tell young kids in the class that if they dont want to get picked on at school to walk around looking confident, not cocky, just confident. Breaking is a useful tool in training, those that understand breaking and why its done realise this. Its like forms/kata, people who dont do MA look at them and wonder what use they could possibly have. Those that do them know better.
I do agree that breaking can add a confidence.
However, if a teacher realizes there are other methods, they would not have to use
breaking (or ranking) to instill this.
Other schools do not have these.
(I have studied at other schools who did not have breaking. Are we to conclude that without breaking, there is no confidence building?)
Nor does the majority of society.
Confidence can be obtained even without martial arts (breaking-ranking)
Speaking of bullies, some bullies would go after anyone, confident or not.
In other words, confidence is not the only thing someone can use.
Confidence should not be over-bearing.
Over-confident is a bad thing.
It can become a false sense of complacency
(I know of a few situations this had happened)
Speaking of forms, other martial art schools do not do these also.
Are we to conclude those which do not, have no value?