NX seems to have been designed for those who shoots JPGs instead of RAW.
I doubt it. I've never been a JPG shooter; I felt it was too much of a compromise.
I use Nikon software for browsing, image selections and some editing because the software defaults to using raw conversion settings set in the camera. This saves time as when I view the images, the processing applied is as I have intended. I still refine the image adjustments when needed, but I have a better starting point because while shooting the adjustments made are respected by the browser and raw converter.
Furthermore, Nikon software shows the focus points and settings used in the camera. This helps me see what worked and what didn't and allows me to investigate why.
The Nikon software also obeys the white balance settings made in camera whereas ACR/LR makes its own interpretation of the white balance which is often quite different from Nikon's.
I also like sometimes to use D-Lighting and I can activate this in post-processing using Nikon software. There are also useful tools such as axial color aberration correction and PF flare correction.
Finally, I feel the conversions made by Nikon software look more natural and three dimensional and I feel this is lost when using other raw converters.
There doesn't appear to be a way to import my own xRite-engendered Camera Profiles.
Nikon software is useful for accessing Nikon profiles, picture controls and algorithms and applying them to raw files; other software exists for working with X-rite profiles and algorithms.
NX Studio makes heavy use of the camera's internally recorded Settings and Picture Controls (which are something that I never use).
Right, it produces almost exactly the same results as the camera at the selected processing settings (but with higher quality as JPG compression is not applied unless requested).
It also wants to honour Active D-Lighting (something that is applicable to JPGs); and seems to base operations on other settings included in the camera's EXIF (all of which I inevitably ignore!).
D-Lighting is a good algorithm and being able to adjust its settings when needed is one of the reasons to use this software.
NX also lacks many of the advanced tools (including Color Grading and a Smart Object workflow into Ps) which ACR now provides.
It doesn't prevent you from using ACR. Just set Open with to open Photoshop and voila, you have access to ACR conversions.
Neither did I get the impression that NX is any faster than ACR.
I am sure that it does convert files faster than I can adjust the ACR settings to match in camera settings for each image (if I have made such adjustments). I find it extremely annoying that even after 22 years of NEF file availability Adobe still haven't bothered to read in the in-camera settings and obey them. It's a productivity disadvantage, in my opinion. I time and time again ask them to address this issue but their effort, when it finally came, is half-hearted. ACR now can read the camera profile used but it doesn't do it correctly if I use multiple photo shooting banks in the camera. It always seems to take the picture control used in Shooting Bank A rather than the shooting bank which was active at the time of shooting.
My copy of NX Studio has now taken a trip to Never-never Land via the Uninstaller.
Good for you.
I will use NX Studio for most of my projects for browsing, image selections/deletions, and as a platform to make Nikon raw conversions, launch Photoshop on the produced TIFF images, launch ACR/Photoshop or DXO Photolab as alternative raw converters and editors that I use in specific cases, depending on what kind of processing I want to do to the image. I will still use LR for editing studio photographs which is where I use X-rite profiles (e.g. to homogenize the colors from LED and flash lights, though my subjects often prefer Nikon profiles, I like the X-rite for fully controlled lighting situations), and for when I need to print multiple photographs on one piece of paper, which LR allows in a very convenient way. I generally do the later steps of photo editing in PS or LR. What varies is mostly just the raw converter which I select depending on image.
Luckily there are different software available to suit individual photographers' needs.