That's a pretty cool service. But as usual with these services today, it's totally trivial to make it do something completely different than what's intended:

https://i.imgur.com/VKrfWYm.png

which would make me very wary of hooking it up with an API-key that I'm paying for, since I'd basically be paying for free GPT access for anyone who visits my site, while I would probably only be interesting in paying when they are asking questions related to my topics.