There is an unacknowledged war going on in the world of singing teachers. There are two groups, subdivided into two more groups.
In the first divide, there are those who teach classical singing technique and repertoire and those who do not. Of those that do, there are those that also teach other styles including music theater, jazz, pop, rock, etc. In THAT group there are those who teach CCM styles who have some kind of experience and perhaps also some training and those who teach the same styles that have neither, or almost none of either. Some of them use different techniques for each style. Then there are classical teachers teaching CCM singers who use the exact same approach (exercises and songs) with them that they use with their classical students. In that case, it is up to the student to find some way to adapt what is being taught to what gets used.
Classical training that is based upon function, whether or not the teacher realizes that, can help vocal ability. It can help develop physical coordination and strength over the breathing apparatus, it can help strengthen pitch orientation and musical acuity in general, it can give a voice more consistency and resonance, it can help articulation. It cannot help someone who wants to learn to sing like a rock singer learn to make an appropriate sound unless the person singing is close to that sound in the first place, in which case it might make it better.
How can I make such a statement? All of my own training was classical and I always sang everything and still do. My classical training did not (and does not) help in any way whatsoever when I perform anything that requires a belt sound. I taught myself to do that and what I discovered had absolutely no relationship to what I did in my voice lessons where I sang classical repertoire. I can attest to the FACT that my students who want to belt, to learn to sing rock music and to wail away might be helped by developing head register, but that is NOT a skill that resides in the private domain of classical singing….lots of styles use head register and its resultant effects.
The CCM teachers who know what they are doing are still much in the minority, but that won’t be for long. More and more teachers are realizing that CCM styles have their own parameters and that attention must be paid. More schools are starting Music Theater programs every year because they make lots of money, and someone has to teach those courses. Sooner or later the ones that don’t know what they are doing are going to be discovered for the frauds that they are. Won’t be too quick for me.