My way of thinking...when you put flowers in a water jar, you give them a clean cut, so they may drink better.
With fig cuttings, I shave slices off the cut end until I see green cambium, then I give the bottom of the cutting a couple of scrapes, and I let the cutting sit in a water/clonex solution for a couple of hours before putting it into sphagnum. My theory is that a clean cut will expose clean, working fibers.
I've noticed that a ring of roots forms just inside the cambium, on the bottom of the cutting, not just on the sides of the cutting.
I've also noticed that the pith at the bottom feels harder, and doesn't recess or disintegrate.
Different varieties have different characteristics, but the symptoms of a cutting that won't drink properly (for me) seem to include a pith that cracks and separates, or feels overly spongy.
Of course, there are people that would purposefully smash the bottom of the cutting before sticking it!