IMO Google did a good job trying to explain the different features that are on-device vs off-device, but with so many features there's inevitably going to be some confusion
AFAIK here's some on-device vs off-device features using generative AI:
- The new updated Magic Eraser is on-device and features generative AI, but note that Magic Editor is different and off-device
- And Recorder will be able to provide summaries using generative AI done on-device, but note that Google Assistant with Bard's summary feature will be off-device
- Zoom Enhance will be on-device and feature generative AI, but note that Video Boost with Night Sight Video will be off-device
- Gboard's updated Smart Reply will be on-device and feature generative AI, but note that Gboard's new updated proofread is off-device