This reminds me of the trams in Manchester, which play the recorded sound of a horn through some little tinny speaker. I'm sure it's cheaper than having an actual noise-making device (I think other trams use bells?), but it sounds ridiculous.
If you're going to fake it, you should at least do a good job of it.
This discussion is very reminiscent of the debate over skeuomorphic user interfaces. As with the transition from physical interfaces to virtual ones, which has drawn interface designers towards the use of skeuomorphic elements to varying extents over the years, we are in another period of technological transition away from normally aspirated internal combustion towards quieter, more efficient means of making motion. To ease the transition for the conservative masses, some degree of skeuomorphism will be needed at first (although I personally think that creating synthetic engine noise is a horrible, horrible idea!).
If you're going to fake it, you should at least do a good job of it.