I guess you do not have kids or other family members that do not always carry their phone everywhere (if they even have one, which I am sure most small kids do not have). Even I who do carry my phone almost all the time personally still use our existing Google Nest / Google smart speakers a lot for hand-free voice control.
I believe that most common usecases are when and where handsfree operation makes sense, like example in the kitchen while your hands are busy, with usecases like controlling lights (brightness or ON/OFF), set/operate timers and reminders or alarms, adding stuff to shopping lists or to-do list, and music controls.
Regardless, there are several usecase reasons that appeal to mainstream users and that is why Google and Amason have each sold more than 500,000 Google Nest / Google Home and Amazon Echo / Alexa smart speakers each ao far.
Check out result in this wish list poll once you done it yourself: