The rules are almost certainly different from place to place.
Where I live, skateboards, hoverboards etc are legally rated as toys and are not tested from a road safety perspective.
”scooter” isn’t a clear definition. The stand-on would most likely qualify as toys too, while the ones looking like vespas would be considered mopeds or motorcycles according to engine power.
Ebikes are generally OK, unless tuned or home-built.
One stock-from-shop will be sturdy enough and have brakes enough for the speeds it’s expected to reach.
They’re not fool-proof though. There is a (IMO well-founded) concern that there will be an initial rise in bicycle accidents as ebikes attracts a number of new and inexperienced riders to take to the roads.