Because I would test if it's keeping its word, like periodically or spontaneously asking both whether it can _import_ the context from one chat to another or, judging the conversational flow between topics.
Maybe we're on different wavelengths on this issue but practically speaking, it hasn't spilled or splattered contexts from different chat topics.. yet.
I asked ChatGPT to isolate individual chats so as to not bleed bias across all chats which funnily enough it admitted doing so.
When I asked Grok, it said it is set as the default out of the box.