At what point does it become valuable to move beyond 1000 grit?

Obviously, if I want to get stupid crazy sharp I'd want to, but what I'm more curious about is what kind of use cases I'd be looking at that justifies chaining up the grits.

Currently I have a Shapton 320 and 1000, and these work great for what I do in the kitchen with the knives I have (all Shun Kanso), and I'm wondering if I felt like going for a couple of the higher grits what I'd be getting and where that'd actually be valuable, versus where it'd just be nice but not actually perform all that better than where I'm at currently.