Holy shit, could I... write thank-you emails this way? :-O
I find thank-you notes horribly difficult to write for some reason, especially when the gift is not well-aimed (which is... usually, to be honest). I often end up skimming through 10-20 sample notes online before I can grind something out. Anything to make that process easier would be worth considering.
(This is honestly the first time I've seen a personally useful application for this tech.)
I know that's not the point you are after but that sounds like such a simple problem to solve.
Why are you thanking someone for a gift? Because they thought of you and went out of your way to get you something, and you appreciate them doing that.
A friend struggling with Christmas cards tried it and... yeah, it's great for that purpose. You still need to give it relevant context / facts, but it works.
I like that you can prompt "longer and with with more tangents".
You would probably enjoy Bureaucrats and How to Annoy Them[1] by R.T. Fishall, a nom de plume of Patrick Moore (of xylophone fame [2], maybe some astronomy too).
A few days ago, in anger, I asked ChatGPT for an email to Apple and I must admit that I finished the prompt with "The aim of the mail is to waste as much of reader's time as possible."
It was quite good, especially after a followup prompt "Not confusing enough. Make it more confusing.". But of course I didn't send it in the end.
I find the act of getting an AI to write this kind of thing for me to be deeply entertaining.
So even if I could have written the letter myself, I would much rather do it like this instead.