In many cases, the superfluous nooks and crannies on 5-over-1's are mandated by local zoning rules that call for "façade articulation" on buildings occupying larger amounts of street frontage (I suppose to conceal the unthinkable horror of a big building existing in a city).

See e.g. Portland, Oregon's façade articulation guidelines: https://www.portland.gov/sites/default/files/2020/lu_buildin...