There is wisdom in that.
I'm frequently drawing from "Life/Still Life". The other day ago I
drew an artichoke for the first time, with a sepia ink pen on paper. I
actuall drew 2 sketches. The first sketch, was drawn from life, and
came out very well, and for the second one, I took a digital pic for
reference, and sketched from the image on my monitor. That one
produced a fair, but not great result, even after I embellished on it,
with details from memory. When you take a picture of something, a lot
of it's essence is lost in the interpretation from 3 dimensions to 2.
So that leaves you sketching from second hand, and your intentions to
produce an accurate drawing, have failed. The artichoke is a very
complex object, that lends itself best (By far) to life drawing. Thus
when you draw it, as you mentally, dissect it, you get a feeling for
how it is composed. The leaves grow out in a pattern, however, not a
perfect pattern. They all have an individual shape, plus they all wrap
around, a roundish center spiking upwards. As I have discovered, they
are an indispensible subject matter for drawing exercises.
Back to "Life drawing" vs. "reference pic". While it is true about,
drawing certain objects from "life" as opposed to "reference", I still
draw and paint landscapes from both plein air, and photograph, and the
loss of visual information does not to be as severe as in the
"artichoke' experiment.