I never liked talking to technology, and I’m not elderly either. I don’t know why people find this better than just pulling out their phone and tapping a couple of buttons.
Sarcasm aside, voice is another interface. A mouse allows things a keyboard can't do alone. Touch and haptics allow things that a keyboard and mouse doesn't, and voice allows things that the others don't.
Alexa and Co aren't just voice interfaces though, they're speech to text combined with NLP. It's the equivalent of knowing ls, find, grep, sort and using that to display the attributes of the newest mp4 in your folder versus typing in 'what is the newest video in my videos' and getting the same answer. These devices support context (if I ask Google what's on today, it will give me my calendar, and if my partner asks it will respond with theirs), are intuitive, easy to manage and cheap. It's no wonder they're so popular