Like Soldier said, its an excuse to fall back on when things don't go as planned (whether "they" intent to or not).
Knowing some of this doesn't hurt, but it also does nothing to help the individual progress towards their individual goal. By an individuals own definition: if to skinny, eat more, to fat, eat less.
Expanding this to limb and torso lengths, I believe some knowledge can help a lifter choose to lift from better positions but past that, it goes back to the conclusions on mesos, ectos, and plasmas. A long torso doesn't lead to a weak deadlift - a weak back leads to a weak deadlift. Long arms down lend itself to piss poor pressing weak arms and shoulders do.