A voice command takes longer to execute than a press or flick of a finger IMO.
It would be interesting to see what the cognitive loads are between a physical movement and a set of voice commands. I remember reading a study that found talking to another person in the vehicle was the equivalent to having had a certain amount of alcohol. I'm sure there's a difference between voice.commands and conversation, but interesting nome the less.
Until the voice command fails and you have to resort to digging through a touchscreen UI.
For whatever reason, my wife's voice does not do well with voice control (despite being an American with an average American accent). And I have a slight Scottish accent (pronounce my Rs and /hw/) which, despite being mild (lived in the US for nearly 40 years) still causes trouble with voice control.
In my Model 3, voice commands work flawlessly for my wife.
For me, it never hears me. Doesn't matter if I talk loud or quite, fast or slow. I'm a native english speaker with no regional accent. Tesla also has no explanation.
Thing is, even if it worked for me, I'd still trade it for dedicated buttons. It borders on aggravating when my wife is driving to be mid conversation and have her suddenly yell out "wipers on".
It would be interesting to see what the cognitive loads are between a physical movement and a set of voice commands. I remember reading a study that found talking to another person in the vehicle was the equivalent to having had a certain amount of alcohol. I'm sure there's a difference between voice.commands and conversation, but interesting nome the less.