I can imagine lots of things- mainly around making short summaries so the user can choose things more easily, or maybe as a smart autocomplete.

I can imagine a home automation app helping you build a workflow with an LLM. Or an RSS reader giving you a short summary of each article. A health app being able to pull recipes into a standard format. Maybe a fitness app being able to search your workout history if you give it good tools.

Idk I usually use my phone for reading HN on the toilet and listening to podcasts while cleaning, not much else. I don’t know what else people even do with a phone lol. But those are things I’ve done in the past that LLMs could be helpful for!