I worked with a company that conducted some of the research that led to this - a major problem with electric cars at the moment is that pedestrians use the soun

I worked with a company that conducted some of the research that led to this - a major problem with electric cars at the moment is that pedestrians use the sound of cars to a) register them in the first place and b) judge when the car will arrive (speed). If a conventional vehicle is coming around a corner you can hear it, anticipate its imminent arrival and act accordingly (especially important on country roads without a pedestrian sidewalk) whereas with an electric car the pedestrian receives no such audible warning. So yes, the engine noise is a consideration specifically for pedestrians.