Totally agreed. Wish it could be done OTA but in all honesty, none of the car makers other than Tesla seem to have mastered the OTA updates. Leave aside OTA, some of the dealership update experience I've read about has been pretty bad.
The dealer I called suggested this update would take 6 hours and possibly an overnight stay. He said they would first diagnose the problem, search for solution and download the fix if its available and apply etc etc. I told him the specific NIssan code they need to look for and get the fix which is now widely understood to fix the CarPlay issue but he would not commit to doing anything before I check my car in...