Unfortunately, based on the provided text, it is not clear what the watchGPT tool does. The text appears to be a collection of links to various products and services available in the Apple Store, and the watchGPT app is just one of many listed.
Without additional information, it is impossible to determine the purpose or functionality of watchGPT. It is possible that with further research, a description could be provided, but currently, there is not enough information available to do so.