All the shots at the name apart I think this is a very good strategic move. The other frontier labs would die to have this level of surface available for their models as a testing ground, with the current state of things on Apple side the ChatGPT on MacOS integration is probably the best everyone will get for a good time on how a full integration of LLM model with OS could really looks like.

Agents will need a different level of understanding of your activities across different surfaces to act effectively, IMHO the OS is the perfect place to offer it.