CyberGene I find it odd that he didn't reply to me here, so that I can respond.
It's called don't ask, don't tell. Very common in the USA where people (for example) avoid talking politics with friends and family, and has driven us to being unable to find common ground with people you disagree with, and it's driving us on a societal/political dangerous slippery slope (apologizes for the OT).
Let me state my opinion since I don't have that effect, since I have neither the NV-series nor the N-series instruments, but I built one and I considered doing either or neither or both (dampers and dampers/key sensors).
At first I considered having both and I even started building parts for the "fake" dampers. I soon realized that it was lots of work and I asked myself if "the perfect was the enemy of the good", because I might have quit since it was really a lot to do. I considered if I could use the original back action instead (which I still have). Using the original back action would have been relatively easy vs building the whole thing from scratch, however it would have added at least 5" (i.e. 12.5cm) of depth of the instrument. For cosmetic and logistical reasons, I considered the depth of the instrument without that back action already the maximum that was acceptable to me, so I discarded that option pretty soon. However I still entertained the option to have a "purely vertical" back action to build completely from scratch (in one prototype idea, that would have been made by large bolts with progressively more nuts from bass to treble, to also simulate the different damper weights). In such an arrangement, I could have kept the instrument at the exact same depth. If I had installed "fake dampers", I would have measured the dampers themselves, not the keys, and that sounded very neat (and mechanically easier than installing sensors under the keys). Yet, it was a difficult (sub)project to complete correctly (e.g. to make sure things would not get stuck while playing, and that not "clanking metal" noise would be annoying) and would have added a considerable amount of weight to the instrument. Neither was a showstopper (I had the time and the stamina back then, and the instrument was a cabinet-based, not a portable slab), but made me question if the decision were the right one or not.
Therefore, I tried playing my grand piano with the pedal always engaged (to "simulate" the dampers/back-action from being absent) and paying attention to the effect that using the pedal had on the keys. I also discussed the matters with my teacher of the time (a traditional teacher, not my current "maverick" Phil, FWIW). To make a long story short, with the dampers disengaged I could play faster and more accurately, and that piano teacher (a professional concert pianist) told me that pressing the pedal even if it's unnecessary is a trick that sometimes professionals do to achieve lighter, faster and more accurate play. Not sure how widespread the thing is (do you have any opinion about that, @David Lai ?) but that was enough to convince me that I did not need the damper "simulations".
I did not so aggressively go with exploring the strict need for key sensors, but I did a bit, and with the electronics and firmware I have I realized that key sensors greatly improve the accuracy of the timing of the note-off messages (and that is even before looking at the velocity of the note-off messages). Now it's possible that a mechanically more accurate action than mine and a more sophisticated firmware could make the timing part moot, but the velocity part will remain. Maybe @gzpiano has an opinion on this? I know that he more extensively tried playing with and without the key sensors and (if IIRC) he found that he can "live without them", but slightly prefer having them.
So I guess I could have just said that I fully agree with @CyberGene on this
