There's a lot of little use cases. Hand free cooking stuff (set a timer, home many tablespoons in a pint). Device control, faster to turn off a TV with voice than dig for the remote, or play a playlist/skip songs. None of those really save that much more time than the old fashion way, so concerns about privacy mean things get done the old way.

I know some people like having them in if they have frailty or mobility concerns, which is probably the only really new usecase.