Seems like a reasonable thing to add. Imagine how impersonal chats would feel if Gemini responded to "what food should I get for my dog?" with "according to your `user_context`, you have a husky, and the best food for him is...". They're also not exactly hiding the fact that memory/"personalization" exists either:
https://blog.google/products/gemini/temporary-chats-privacy-...
https://support.google.com/gemini/answer/15637730?hl=en&co=G...