It's ultimately just a prompt, self-hosted models can use the system the same way, they just might struggle to write good SQL+vector queries to answer your questions. The prompt also works well with Codex, which has a lot of usage.
If you're not willing to pay for your own LLM usage to try a free resource offered by the author, that's up to you. But why complain to the author about it? How does your comment enrich the conversation for the rest of us?
