Maybe it's because I've never been to Vegas, but I still don't think the city would have any more of those things than, say, New York.  I can't see why it'd have more computers or cars or atm's.  Maybe security systems and things like that would be more common, but if Harry can walk into a museum of natural history, or go on a boat without causing it severe damage, I think we could get away with Vegas as a setting.  I don't think the mechanics are a prime reason to turn it down, anyway.  If its unpopular thats another story.