Hi KillerKu,
Funny you mentioned the guitar because that's exactly where I learned this idea from. I met Marty Friedman at a guitar clinic some years back and when I asked him about how he came up with his style it was the same method I described in this video. You use a reference you are trying to learn and you try to study it and reproduce it.

Over time the traits will be embedded into you and you can forget about it and just sing.

Yes I agree with you the macro detail as you pointed out is just as important. Art is always about balance between fine detail and macro detail.

Even with original songs it can be used. Often times I notice people can feel lost when singing their original songs because they don't know what it "should sound like". You can still have references such as "I want this part to have the same kind of feeling of this song I love" and draw the same kinds of ideas from it.

Mixers use reference tracks to see how their songs hold up also. Artists use references to see how their paintings hold up. I used to be an animator and reference was always the king. We would even record ourselves acting out the movements and study actors on film to use as reference.