> There is no real advantage to using a custom GPT over adding a custom prompt to a project
The two features, namely Custom GPTs and Projects, are orthogonal. This is because a Project is for related explorations of a theme, whereas a Custom GPT is for unrelated explorations of a theme.
> chat history
What chat history? Each chat is in the user's history by default, which is how it's supposed to work for Custom GPTs. I don't need a filtered chat history for a Custom GPT like I do for a Project.
> It really seems like they stopped working on custom GPTs and just expect users to use projects instead.
That's more a personal belief rather than a conclusion; it's not even a formal declaration by OpenAI.