The only reason for the voice interface is to facilitate the production of a TV show. By having the characters speak their requests aloud to the computer as voice commands, the show bypasses all the issues of building visual effects for computer screens and making those visuals easy to interpret for the audience, regardless of their computing background. However, whenever the show wants to demonstrate a character with a high level of computer mastery, the demonstration is almost always via the touchscreen (this is most often seen with Data), not the voice interface.
TNG had issues like this figured out years ago, yet people continue to fall into the same trap because they repeatedly fail to learn the lessons the show had to teach.