The only two that match up with the Windows piece of the puzzle are Dave Kleiman and Paul Le Roux. Of those two, Paul Le Roux had a interest in online gambling. Guess what the first Bitcoin release had references to.
Function calling is a great step towards actually production-izing LLMs and making them extremely robust - I remember when GPT-3 API first came out and I was furiously making sequential calls with complex if/else and try/catch statements and using a couple of Python libraries for the simple reason...I need the output to be a valid JSON. It was surprisingly hard until function calling solved this.
The difference between the structured output of json mode is that the model can choose which set of structured output (matched to various function definitions). Subtle, but pretty cool and powerful.