Technically this isn't a new feature. It’s an improvement of the existing tool. In the past this tool did not faithfully rotate all annotation elements consistently. We’d often find some annotation was either not rotated at all or moved into different positions. They've revisited the code to ensure more consistent results. It’s not a guarantee they've resolved everything since they can only tackle issues that have been identified as problems. We are pretty ingenious at doing things with Revit that the developers didn't imagine. Hopefully we’ll find that it is more reliable when/if we need to use it.
Let me take this opportunity to remind you that Revit’s bias has always been to create a model or building with Project North in mind FIRST. FORGET about the real orientation on site, initially (please). That’s what using Rotate True North is for and Acquiring Coordinates.
Those tools existed long before Rotate Project North. In fact it was only added because people can’t seem to remember to start their project using a Project North orientation. If you’re interested in more of my writing about using Shared Coordinates you can check out my blog post summary.