Wide range of usages, given its pictorial and optical qualities, weather sealing, close focus, and stabilization. Very convenient FL, by the way. At ease with portraits, social events (despite bulk and slow AF, but MF is good enough), architecture.
Image quality is very appealing; I'd say "delicate rendering", as contrast may be milder than with, say, recent Zeiss lenses; Users should not get blinded by absolute resolution figures (yes, Otus is better, so what).
Size and weight