iPhones use a lot of these. There's a bunch of little features that run on the NPU.

Suggestions, predictive text, smart image search, automatic image classification, text selection in images, image processing. These don't run continuously, but I think they are valuable to a lot of users. The predictive text is quite good, and it's very nice to be able to search for vague terms like "license plate" and get images in my camera roll. Plus, selecting text and copying it from images is great.

For desktop usecases, I'm not sure.