Something about "Hey Siri, ..." is much more grating to me to say than "Alexa, ...". Maybe it's just that conjunction of phonemes being rare in English?
Try saying that three times fast. Actually, try saying it just once fast.
I always end up spitting out something like "Okaygggeellggglle"
Amazon has it right on this with Alexa.
People want to believe they're talking to a personal assistant, even if that isn't true, and Google is stupidly stripping them of that.