I can only speak for myself but it's far easier, psychologically, for me to go out and walk somewhere when I have a goal besides just walking. While a destination is not necessary in the strictest sense, not having a reason besides exercise is a substantial barrier.

If you can walk to the places you need to get to, then you don't even need to go out of your way to hit the step goal.

It's a shame that we (Americans) don't build cities this way, instead requiring that we drive everywhere. It's bad for the environment as well as our health.

Yeah but the walk in those environments just sucks. Loud traffic, no sidewalks, nothing to look at. When I visit Canada, I always miss walking in the woods, because the paths just don't exist. In Germany they're literally everywhere.