I thought that was odd too. There are lots of ChatGPT clones implemented as native MacOS apps.

The main advancement in TFA is using the new Container Swift API for local tool use. That functionality would probably be a welcome contribution to any of these:

https://github.com/Renset/macai

https://github.com/huggingface/chat-macOS

https://github.com/SidhuK/WardenApp

https://github.com/psugihara/FreeChat