I'm not sure how you would regress a button that physically doesn't exist anymore. Also, if you're that scared of future bugs that don't exist, then you should probably throw away your smart phone.
As a side note, whataboutism adds nothing of value to this discussion about the Google Home and Amazon Echo.
Also, talking about your contradictory behavior with your smartphone isn't whataboutism, unless you want to avoid addressing your hypocrisy, because smart phones are susceptible to the same blanket fears you have with homes/alexa. To critique only the latter, and not the former (which you use daily), is not fair.
Per Google's own site: "Long press to trigger the Google Assistant."