It's pretty clear if you see what's happening on current phones.

Autocorrect that works. Reply suggestions that almost work, just need to be tad more accurate (probably more of a data access issue than model) and a tad faster to look completely seamless. Screenshots with automated text detection and OCR and automatic interpretation (different suggested actions for when something on the picture looks like a web link, phone number, postal address, e-mail, or QR code, or an event poster). That's just a fraction of things I saw showing up on my Samsung phone over the last 6 months.

For over a year now, you could get a much better autocorrect and spell/grammar check, and a translator all in one, if you just pasted your text to a frontier model and asked it to check for errors or translate into target language. Now imagine being able to go through a round of such checks in a 1/100 of a second. You could have this running every keystroke, and suddenly the inline autocorrect/checks would not suck anymore.

Auto-linkifying that can correct for typos and doesn't need careful regex tuning because it understands from context what is meant to be a link or not. That's just one of many obvious things possible once you get local models running fast enough. Tip of an iceberg, and the first step to imagining all the other potential uses is to let go of the two mistaken beliefs people hold on to:

1. That LLMs are about written language. They're not; ever since "multimodal models" became a thing, tokenization extended to visual and audio space, and now textual and visual and aural inputs are all just regular, first-class tokens.

2. That chatting with the models is the only optimal way for end users to interact with AI. That's just artificially limiting yourself to the space of chat-based UI.