It's all up to the user. There is NO way to say that one method or another is "correct".

Just as an example, take the quote from SVDL (Sorry for picking on you Steven)..
"I can draw. Not very well, but I can use perspective and I can see when proportions are "wrong"."

When was perspective drawing discovered (and I use that word advisedly)?
IIRC, the method of creating perspective on a flat surface was discovered somewhere in the 1400's, by Brunelleshi(SP?) in Florence. Before that time "art" was curiously flattened (but it's still called art), and a lot of it is in major museums andart galleries.

He discovered a method. It worked. It didn't invalidate what went before.

Moving on...
I don't use Poser to make pictures. I use it to explore the possibility of making a picture. I use it to try various poses, various lighting options, various camera angles etc.

I usually (but not always) have a vague idea of what I want to create and use Poser as a tool to explore the possibilities.

If I tried to make a sketch before-hand (as if I could) I'd be limiting myself to what I could draw. Which is not a lot.
So, in effect, I use Poser to make my sketch.

Then I put it all together in Vue:-)

Cheers,
Diolma