First off, screw tutorials that say there is an 'only' one way to do anything. There is no 'one' simple way to deal with any vocal. Ever. Especially vocalists that we may not feel that are 'vocalists'..
Depending on the type of vocal or whatever genre it is, it is always different.
I personally like to record a scratch vocal and see what is possibly needed later. Then decide what possibilities might help the recording. Mic placement, headphone on or off one ear, flavor of pizza, or maybe the smell of my cologne... LOL
A true heart felt performance is always the best ever. We all try to find that as the holy grail.
That does not always happen, so we sometimes have to place them together.
So back to the original question, if the vocal was great to start with, why would anything need to be done to fix it? That is really the question.
But then, that is the world we seem to live in now. Gone are the days of the great musicians just doing it right the first time...
Not bitter, just honest.