Claims like this one seriously undermine the (worthwhile) privacy movement. Convenience and entertainment _are_ worthwhile uses of technology. Those of us with an understanding of privacy and surveillance technology might well make the judgement that certain forms of convenience and entertainment are not justified by the intrusion that they present - but to claim that there is _zero_ benefit to those technologies just makes you look out-of-touch or cranky to the very people who would benefit from more awareness.
Would I give up all my credit card details in order to have a marginally better music playback experience? No. Would I tell a company my birthday if they paid me $1,000,000 for it? Yes. There is a continuum of "privacy/payback evaluation", and different people lie at different points along it.
Alexa, Siri and co. do have legitimate use cases for people, even if they may not be useful for -you-.