biking is just walking while sitting down

Using skateboards, scooters and wheelchairs counts as walking

In urban planning, walkability is the accessibility of amenities by foot.[1] It is based on the idea that urban spaces should be more than just transport corridors designed for maximum vehicle throughput. Instead, it should be relatively complete livable spaces that serve a variety of uses, users, and transportation modes and reduce the need for cars for travel.

But I get what you mean. I think the idea in this was just to show all sorts of different forms of travel