We love our 718 BS, which has SC and Sport PASM, but lacks PTV (which adds the electronic limited slip differential). I cannot say how beneficial PTV would be, but after only two half-day HPDE's, it's obvious our car would be somewhat more stable on track with the limited slip diff.
PTV was originally a must have, but couldn't find the right CPO with that option. Regardless, I am quite satisfied with the performance of our BS and would not trade just to get PTV/LSD. That said, I am currently searching for the right pre-owned GTS. Not for LSD, but to decrease the probability of encountering any potential track related heat soak limp mode issues that have plagued the "S" since inception, something I was not aware of at time of purchase.
You will find the issue noted in several threads on this and other forums. I have yet to experience limp mode, but track temps in the Texas Hill Country hit 100+ fairly frequently during our nuclear summer months. Thus, I view getting PTV & LSD (standard on GTS) as simply a bonus, even though they will provide me with fairly limited benefits for DD or long trips.
IMHO those who plan to rarely or never track their cars (perhaps the overwhelming majority of buyers) probably won't view PTV as a critical option. However, well informed buyers who plan to heavily track their cars are likely to view the heat soak limp mode issue as far more critical and avoid the "S" all together...again, MOO.