A quick moan about this:
As a long-time paying subscriber of ChatGPT (and their API), I am extremely frustrated that the "Chat history & training" toggle still bundles together those two unrelated concepts. In order for me to not have my data used, I have to cripple the product (the one I'm paying for) for myself.
It's great that they're making the product available to more people without an account but I really wish they would remove this dark pattern for those of us who are actually paying them.