One city across a strait
The Bosphorus divides the two shores without dividing Istanbul into two separate cities. Neighbourhood character varies within each shore as much as between them.
Different sightseeing priorities
The Old City’s Byzantine and Ottoman monuments lie on the European shore. Kadıköy and Üsküdar introduce Asian-shore markets, waterfronts and neighbourhood life.
The crossing is part of the visit
A ferry crossing gives a useful view of the city’s relationship with the water. Check the actual piers and return connection rather than treat every Bosphorus cruise as an Asian-shore visit.