I think they're slightly overegging the CO2 aspect. Yes, it could be a boon, but it does depend on how the scooters are used. Their real benefit I feel is not in the way they replace other vehicles but in how they reshape journey patterns. The way you see, for instance, students going out in little fleets on a Saturday night. If I had a teenage daughter, I expect I'd far prefer she come home drunk on an e-scooter than in an also-drunk friend's car, on foot through a dodgy area (which is usually where the best clubs are), or an unlicensed taxi (please don't pretend these don't exist or even are unusual). Or the way people pick them up for semi-impromptu shopping trips. Or to get to the station for a train to (wherever). Without bus schedules or routes, without expensive taxis, faster than walking, easier than cycling. It's no wonder they arouse such a lot of status quo hate.