Yes, the tools all technically work after hooking LN to Krita, but the perspective rulers are static and keep their absolute size and placement regardless of changes to the viewer. When you pan and zoom, the rulers keep their size and placement relative to the document, which means your center line, horizon line, VPs, tick distance, etc., are always spot on, regardless of changes to the viewer. With the plugin installed, the user experience with perspective rulers in PS is very different than it is in Krita.

If you’re not familiar with the Lazy Nezumi plugin for Photoshop, I can understand why you’d feel this way.