upsides versus walking: - 10x further distances - 10 blocks feels like 1, it's simply amazing. You can see parts of the city that are impractically far or bordered by boring/industrial zones.
upsides versus biking: - slow enough to "take in" the sights, where biking definitely feels like you've "lost" something. - more stable / feels safer - much easier to stop & start, and easy to lock up for a few minutes. - about the same speed as manual bikes (in practice) but slower than e-bikes
real downsides: - safety: if there's no bike lanes, then scooters can become hazardous. In particular, because they travel quickly, you can be safe one minute and then quickly have conditions degrade. The risks of medical attention vary by city - developing countries can have limited medical care; US medical care is $$$$. - disallowed & slow zones: it can be *VERY* annoying to have the scooter beeping at you, refuse to go, refuse to lock etc. And the GPS is imperfect, so you can be on the border of a legal zone and have it stop. I've had to walk scooters many times. - cargo: tough to carry significant cargo, e.g. groceries quickly become hazardous.
perceived downsides: - return-anxiety: what if there's no scooters? ==> rarely happens, but if so, then take an uber! - range-anxiety: what if it runs out of juice? ==> I've ridden a lot and never come close... - one scooter available for two people? ==> if you're careful, you can put two people on a scooter, then scoot to the next scooter (apps all have maps of available scooters)