Thing is there are a lot of old people.
I expect there are even younger people than I who used rotary phones as kids.
I just bought my first smart phone and spent a while in developer mode quieting it down to extend battery life so some old people can do this.
Some can, many won't. Eye sight and dexterity problems have a lot to do with this. When you can't see and your hands shake it's a lot easier to just "hey google call so-and-so."