Scooters have automatic transmissions, motorcycles have manual transmission. Scooters are easier to drive, motorcycles have less problems.
Scooters are step through, motorcycles require you to throw a leg over the saddle. If you have leg/knee problems and/or are wearing a dress, a scooter is “better”.
Scooters have floorboards to keep your feet and shoes wet when the streets are rainy.
Basically, scooters have more comfort, but cost more.
Safety is same — neither scooters are motorcycles are safe or unsafe. People are unsafe.