You are saying something, though. To your recipient, it doesn’t matter whether you typed your message yourself, you spoke it through TTS, you asked your life partner to dictate something for you, you chose a response from a curated selection of messages hand-picked (by an AI that learns how you write) for you, or a myriad other ways that message could end up ready to send back.
If you want to say “aww so cute” (and again, remember that these responses grow more and more similar to your writing style over time — so if you would never be caught dead saying “aww”, the assistant will know that in time) in response to your friend’s kid, you’re still saying what you want to say, even if you don’t have to type a single word.
If you don’t want to say “aww so cute”, you’re more than welcome to type whatever you want instead. Predictive responses are a helpful tool, not an intellectual prison.