Note that linear ways with an outline in addition should be area:highway=footway (or whatever kind of way), while pedestrian areas with omnidirectional movement is highway=footway + area=yes. (OSM carto doesn't render the former) The  difference is outlined here: https://wiki.openstreetmap.org/wiki/Key:area:highway

Unfortunately Chicago's lakefront parks have lots of these mistaggings ("tagging for the renderer"), and can  also break routing at times (for example pedestrians will be routed down this cycleway: https://www.openstreetmap.org/way/1124504884)