A bicycle is difficult to bring on many forms of public transportation, and can require a change of clothes. Scooters can fit on a luggage rack.
Walking is much slower, of course.
I enjoy walking and cycling, but not for my commute. It takes an hour to walk vs. 20 mins to cycle or scoot. If I cycle I arrive unavoidably sweaty. My scooter is fantastic for commuting. When I want to walk, I go to the lake with my wife.
It’s faster than walking. And just try cycling in a skirt suit.