The "Chat" part of ChatGPT is one interface.
I've found the most use for it in doing zero shot or few shot classifications of natural language without needing to build and run a model on my own.
For example - Show HN: GPT Classifies HN Titles https://news.ycombinator.com/item?id=34156626
Classify following titles into one or more of {US Politics}, {World Politics}, {Technology}, {Security}, {Current Events}, {Boasting}, {Curiosity}, {Unknown}
Which, when I ran it back then produced:
34152137 Technology: Lite XL: A lightweight text editor written in C and Lua
34151880 Curiosity: Hydrochloric acid is more complicated than you think
34156235 World Politics, Current Events: Apple Japan hit with $98M in back taxes for missing duty-free abuses
34152333 Technology: The Architecture of the Lisa Personal Computer (1984) [pdf]
34151951 Curiosity: The Zen anti-interpretation of quantum mechanics (2021)
34155009 Unknown: Added 49 volumes of Arkansas, Mississippi, and Tennessee law
...
Another one that someone made on HN data - Show HN: A structured list of jobs from “Who is hiring?”, parsed with GPT
https://news.ycombinator.com/item?id=35259897The direct API interface is incredibly useful. The chat interface is useful for an expiatory domain into the classification and knowledge contained within the model (be wary of hallucinations), but the direct calls where you know the information you have and want - its classification and parsing of unstructured data is very powerful.