With CLI, you usually can type help or add a -h to the command or something like that and you'll be presented with options and examples.

You really don't have this option with voice. On the other hand, when I visited my mother I was surprised that she figured out that Google Assistant can provide her with nutrition information. She would have never figured out by herself on a CLI or menu because it's very intimidating.

This somewhat contradicts my previous comment about how much I dislike voice interfaces but they probably have some strengths.