These extra walkways seem odd to me as a user of the map. They are normal sidewalks, rather than a separate path, so it seems inconsistent to have these marked. It would also seem strange to add these parallel walkways for every road with a space for pedestrians.
My interpretation of [the wiki](footway=sidewalk) is that since these are not separated, these paths should be removed, and the roads tagged with sidewalk=both.
I'll happily start removing these kinds of redundant paths if others agree that it's the correct approach.