Come da OSMwiki, "If there is a small (one company/property) area of commercial (or similar) landuse within an otherwise residential area, you can still decide to use landuse=residential for the outline of the whole larger area as a preliminary solution. You could later draw a separate area tagged with landuse=commercial for that commercial establishment."
Quindi o vengono mappati i singoli landuse o si tiene la principale area residenziale mappando poi le attività (penso prevalentemente commerciali o uffici) come punti.