Aside from the idea of looking cooler because you're on a scooter instead of a bike I still have a really hard time understanding why someone would want one over a MTB or a recumbent. At the same time its one less hummer and I would rather live with a bunch of dumb(image obsessed) scooters then a bunch of blind SUVs.
Back to the reasons for a scooter.... ive seen people here argue that they are safer but I haven't the slightest clue why. Ive seen people say they are more comfortable but they couldn't possibly be better then a nice laz-e-boy style recumbent. The one thing I wonder about is aero dynamics, seeing as how scooters are usually rounded and stuff do they have less drag then a regular MTB?