Post's question:
Are LD shafts only really helpful on long shots w/ a lot of side spin?
Some consensus here that LD shafts are helpful on all shots with a lot of side spin; not just long shots with a lot of side spin.
See Sharivari and side-spin effects using his low-deflection shaft (it was probably JFlowers SMO he used) on short-length shots. If he had used a high deflection shaft, more aiming adjustment would have been necessary.
See video at 1:00
Sharivari was interesting as he claimed there was only squirt/deflection at low speeds causing left-spinned cue ball to deflect right versus swerve/masse effect at high speeds and more butt-elevated cue with left-spinned cue ball moving left. And, unlike another YouTuber, showed aiming adjustments necessary even when using a LD shaft.
Sharivari limited discussion to speed effects and elevated cue. He did not discuss other methods of adjusting for spin besides LD shaft, speed and cue angle.
One comment did discuss other methods for spin adjustment:
I love your teaching style, Sharivari, but Dr. Dave’s FHE/BHE system is far easier to use across the speed/distance spectrum.BHE (pivot) for hard shots, FHE (parallel) for softer shots, and a mix of the two depending on the specific distance and speed required.The real beauty of this system is that it cancels out the need to change your aiming point. I use side-spin a lot (a good coach would say I over-use it), and after learning this system, I aim through the ghost ball on every shot, at any speed and distance… so it even cancels out spin-induced throw (SIT). I’m not going to link to this out of respect to Sharivari, but we are all students of the game, even the masters.

To which Sharivari replied:
I use a natural approach, which is essentially a blend of BHE and FHE.