It might work, but it is difficult to walk just for walking: I know people who walk their dog, which works, but just going out around doesn't seem like a good motivation

If you don't find that sufficiently motivating, then you don't care about it enough to use it as an argument for why we should all have to commute.

Before I had a dog, I would intentionally go for walks to think over an algorithm or endpoint I'm writing. People who work in an office do the same thing, often intentionally.

Depends on your neighborhood, but this sounds like a personal preference issue; walking just for the sake of being outside is a liberating experience in of itself. Walk for the sun and for the breeze and the sounds of nature. Or go for a jog.