Thank you for posting about your positive experiences with Alexa. I’ve largely heard negative or “bloopers” (children making large purchases, etc) around using it, and seeing another side of it is extremely helpful.
My general opinion around items such as Alexa is that of distrust. Even if policies prevent companies from using everything you say for advertising purposes, and even if you can turn off some listening features (which I don’t know the details around, as I do not own an Alexa or similar device), policies can change with new leadership on both company and government levels.