I find this far more useful than a suite of tools or "AI agents" which always work well in a controlled development environment but not so much further than that.

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.