The KeepRight Issues in the Open Street Map Data showed me that exact message, and I marked it as fixed today. The Wiki page from https://wiki.openstreetmap.org/wiki/Key:abutters says, "This could be used for rendering if landuse=* area information is not available." So it seems to be saying that landuse around the road should be used instead of marking the road itself as abutters. Perhaps it's not deprecated, but it seems to be discouraged in this kind of scenario.