Even in a car, being able to control the windscreen wipers, radio, ask how much fuel is left are all tasks it would be useful to do conversationally.
There are some apps (im thinking of jira as an example) where i'd like to do 90% of the usage conversationally.
are you REALLY sure you want that?
how much fuel there is is a quick glance into the dash, and you can control precisely the radio volume without even looking.
'turn up the volume', 'turn down the volume a little bit', 'a bit more',...
and then a radio ad going 'get yourself a 3 pack of the new magic wipers...' and car wipers going off.
id hate conversational ui on my car.
I wish car manufacturers stopped with the touchscreen bullshit, but it seems more likely that they'll try to offset the terrible experience with voice controls.