I think you might be confused about the difference between giving the LLM access to your stored conversations during your session and using OpenAI using AI to search your stored conversations.
What the LLM has access to during your session changes nothing but your session.
It’s not some “I, Robot” central AI that either has access or doesn’t as a whole.
You’re getting down-voted, but, yes, this change only really affects user experience.
I don’t know why anyone would think that what the LLM can access for context during your session is a limiting factor for what OpenAI has access to.
If this change freaks you out, the time for you to be freaked out about history was the moment they started storing it.